The State brought appellant Sharron Scheikofsky to trial on the charge of second-degree murder of Lowell Scheikof-sky, her husband. A jury convicted appellant of voluntary manslaughter, and the trial court sentenced her to ten to fifteen years in prison. Appellant appeals her conviction and sentence. She asserts that the trial court erred in the instructions it gave concerning her theory of the case — self-defense — and concerning the State’s burden of proof on the self-defense claim. She also asserts that the trial court abused its discretion by imposing an excessive sentence on her.
We affirm.
The trial court gave two of its own instructions at trial, one concerning self-defense and one concerning burden of proof. Appellant did not object to the instructions.
Rule 51, W.R.C.P., applicable to criminal appeals via Rule 31, W.R.Cr.P., provides:
“ * * * No party may assign as error the giving or failure to give an instruction unless he objects thereto before the jury retires to consider its verdict, stating distinctly the matter to which he objects and the grounds of his objection. * * * ”
The purpose of Rule 31, W.R.Cr.P., is to offer the trial judge an opportunity to correct erroneous proposed instructions, or at least to clarify them. Downs v. State, Wyo., 581 P.2d 610 (1978); Bentley v. State, Wyo., 502 P.2d 203 (1972). Since no objection was made to the instructions, appellant is precluded from seeking review of them unless she can show plain error as provided in Rule 49(b), W.R.Cr.P.1 Downs v. State, supra; Daellenbach v. State, Wyo., 562 P.2d 679 (1977). The plain error rule is applied cautiously and only in exceptional circumstances. Hays v. State, Wyo., 522 P.2d 1004 (1974).
I
Appellant contends that Instruction No. 13 did not present her theory of the case to the jury, which is prejudicial error requiring reversal. A defendant does have the right to have his theory of the case affirmatively presented to the jury, provided that the offered instruction is sufficient to inform the court of the defendant’s theory and provided that there is competent evidence in the record to support it. Failure to do so is prejudicial error. Goodman v. State, Wyo., 573 P.2d 400 (1977); Benson v. State, Wyo., 571 P.2d 595 (1977); State v. Hickenbottom, 63 Wyo. 41, 178 P.2d 119 (1947).
The question here is different from that in Goodman v. State, supra. There, no instruction at all was given on the defendant’s theory of the case. Here an instruction on appellant’s theory of the case was given, so that the question now before us is the sufficiency and correctness of the instruction. The appellant proposed three instructions which we assume were meant to present her theory of the case to the jury. They dealt with burden of proof, relative sizes and ages of the appellant and the victim, and the fact that the defendant fired several shots.2 The trial court reject*1110ed the proposed instructions and supplied Instruction No. 13 instead:
“A person is justified in the use of force to defend oneself against an aggressor’s imminent use of unlawful force to the extent it appears reasonable to that person under the circumstances then existing.”
The court may choose to present its own instruction covering the defendant’s theory of the case. We said in State v. Hickenbottom, supra, 178 P.2d at 131, that the defendant had a right to have his main defense in the case affirmatively presented to the jury, and that “the defendant’s requested instruction, * * * or one similar to it should have been given by the District Court * * (Emphasis added.)
We think that the court’s Instruction Number 13 affirmatively presented appellant’s theory of the case, and that Mrs. Scheikofsky may have even received a benefit from Instruction Number 13. To claim self-defense, a defendant’s belief about the necessity of defending himself must be based on reasonable grounds. A subjective belief of danger will not alone suffice; the defendant’s belief of danger must also be reasonable. Leeper v. State, Wyo., 589 P.2d 379, 382 (1979); State v. Sorrentino, 31 Wyo. 129, 138-139, 224 P. 420, 34 A.L.R. 1477 (1924); Loy v. State, 26 Wyo. 381, 390, 185 P. 796 (1919). It is quite possible that the jury could have construed the words “reasonable to that person under the circumstances then existing * * * ” (emphasis added) to mean that only appellant had to see the danger as imminent, not that a reasonable person similarly situated would have had to believe danger was imminent. Even assuming this were an erroneous instruction, it is certainly not cause for reversal, since it seems to favor appellant in its statement of the law of self-defense. Mainville v. State, Wyo., 607 P.2d 339 (1980).3
To show plain error, appellant has to show a violation of a clear and unequivocal rule of law and has to show that she has been materially prejudiced by that violation. Settle v. State, Wyo., 619 P.2d 387, 389, citing Madrid v. State, Wyo., 592 P.2d 709, 710 (1979). She has failed to show any harm here, let alone that harm required by the plain error rule.
II
Appellant also objected on appeal to jury Instruction No. 12 on the ground that it failed to adequately and clearly set out the *1111State’s burden of proof on her claim of self-defense and was therefore plainly erroneous.4 The court long ago made its pronouncement on the burden of proof in homicide cases. Trumble v. Territory, 3 Wyo. 280, 21 P. 1081, 6 L.R.A. 384 (1889). In a prosecution for first-degree murder, the trial court gave an instruction that, if the prosecutor had failed to prove premeditation and deliberation beyond a reasonable doubt, the law would presume the killing to be murder in the second degree in the absence of further evidence. The burden, said the instruction, would fall on the defendant to show that the killing was justifiable or excusable. The instruction was erroneous, and the court so held:
“ * * * But if the defendant is presumed to be innocent until his guilt is established, and if the prosecutor must prove every material allegation of the indictment — every element of guilt — beyond reasonable doubt, before he can ask for a conviction, how can the burden of proof upon any question ever fall upon the defendant? * * * ” Trumble v. Territory, supra, 21 P. 1081, at 1083.
Because the instruction in the case before us failed to specifically allocate the burden of disproving self-defense to the State, appellant argues that the instruction could have permitted the jury to believe that the defendant, having raised the issue of justification, was obligated to prove it. However, appellant has to do more than conjecture about what the jury could have believed. A mere allegation of prejudice will not suffice to invoke the plain error rule.
This court examines instructions in their entirety when it is called upon to decide whéther instructions are erroneous. Snyder v. State, Wyo., 599 P.2d 1338 (1979); and Cullin v. State, Wyo., 565 P.2d 445 (1977). They must be considered as a whole and not according to isolated phrases and paragraphs. Hoskins v. State, Wyo., 552 P.2d 342 (1976), reh. denied 553 P.2d 1390 (1976), cert. denied 430 U.S. 956, 97 S.Ct. 1602, 51 L.Ed.2d 806 (1977); and Loy v. State, supra. Here, the instructions taken as a whole stated the law correctly. The State claimed that the murder was accomplished with malice. Malice is an essential element in the prosecution of a murder case; it must be shown beyond a reasonable doubt. State v. Bruner, 78 Wyo. 111, 319 P.2d 863 (1958); and Eagan v. State, 58 Wyo. 167, 128 P.2d 215 (1942). This court and other courts define the term malice as the intentional killing of a human being by another, without legal justification or excuse and under circumstances which are insufficient to reduce the crime to manslaughter. Nunez v. State, Wyo., 383 P.2d 726, 729 (1963); and State v. Sorrentino, supra 31 Wyo. at 140, 224 P. 420. See also State v. Dunnan, 223 Kan. 428, 573 P.2d 1068, 1071 (1978); and State v. McIntyre, 106 Ariz. 439, 477 P.2d 529, 532 (1970). Instruction No. 2 told the jury that malice had to be proved beyond a reasonable doubt. Instruction No. 4 defined malice as the commission of a wrongful act done intentionally without legal justification or excuse.5 Instruction No. 12 told the jury that it was to *1112find the defendant not guilty if it had any reasonable doubt as to the truth of any claim made by the State. The State claimed the existence of malice; therefore, the State also claimed lack of justification, albeit indirectly.
The inclusion of a specific statement of the burden of proof would have been preferable, but failure to include it is not reversible error per se. The test should be whether the instructions, taken as a whole, adequately informed the jury that the prosecution’s burden of proof beyond a reasonable doubt included negating appellant’s assertion of self-defense. We hold that the instructions, taken as a whole, did adequately inform the jury of the State’s burden of proof in this case.
Ill
Appellant proposed several in- ' structions of her own (See fn. 5.) concerning burden of proof and self-defense. She presented argument in favor of her proposed instructions after the trial court had rejected them, and now contends that failure to give her proposed instructions A, C, and D was prejudicial error.
Appellant must meet the burden of showing prejudicial error. Belondon v. City of Casper, Wyo., 456 P.2d 238, (1969), cert. denied, 398 U.S. 927, 90 S.Ct. 1815, 26 L.Ed.2d 89 (1970); and State v. Spears, 76 Wyo. 82, 300 P.2d 551 (1956). Under Rule 49(a), W.R.Cr.P., for the error to be harmful, “there must be a reasonable possibility that in the absence of the error the verdict might have been more favorable to the defendant.” Nimmo v. State, Wyo., 603 P.2d 386 (1979); and Reeder v. State, Wyo., 515 P.2d 969 (1973). Appellant has not proved that possibility here. We have already stated that Instruction No. 13 affirmatively presented her theory of the case to the jury, and that Instructions No. 2, No. 4 and No. 12 taken together adequately set forth the State’s burden of proof on the self-defense claim. We do not know of any case which holds that an instruction must be couched in the precise words requested by a party. A trial court may refuse requested instructions which are correct, as long as the principles embodied in the requested instructions are covered by other instructions. Campbell v. State, Wyo., 589 P.2d 358, 369 (1979); and Benson v. State, Wyo., supra. That also left the appellant free to argue the theories to the jury. Here, appellant could have presented additional self-defense argument under Instruction No. 13 and additional argument on burden of proof under Instruction No. 12.
IV
Appellant’s second issue on appeal is that the trial judge abused his discretion in sentencing her to ten to fifteen years in prison after her conviction of voluntary manslaughter. Appellant had no criminal record. The testimony at the sentencing hearing was favorable. Previous employers praised her work and her attitude. She was offered a job and a place to live, had probation been granted. She had been continually abused by her husband, both physically and emotionally. Appellant apparently felt that decedent drank too much, bathed too seldom, and bullied her once too often. The judge indicated that he considered all those factors in arriving at the sentence. He also stated that he considered the public’s respect and regard for the law, after which he sentenced appellant to a minimum term of ten years in prison— half the time allowed by statute.
This court has stated its approach to sentence review many times. If a trial court’s determination of the terms of imprisonment is within the statutory limits, it will not be disturbed absent a clear abuse of discretion. Hanson v. State, Wyo., 590 P.2d 832, 835 (1979); Jones v. State, Wyo., 602 P.2d 378, 380 (1979); Smith v. State, Wyo., 564 P.2d 1194, 1202 (1977); Daellenbach v. *1113State, supra, at 683. A sentence will not be disturbed because of sentencing procedures unless the defendant can show an abuse of discretion, procedural conduct prejudicial to him, and circumstances which manifest inherent unfairness and injustice, or conduct which offends the public sense of fair play. Hicklin v. State, Wyo., 535 P.2d 743, 751, 79 A.L.R.3d 1050 (1975). That is a nebulous standard, but it is as precise as we care to make it. We have an abiding reluctance to review a trial judge’s determination of sentence. The determination is a burdensome decision which no trial judge could lightly make and which we will not lightly overturn.
Here the trial judge apparently balanced everything favorable in the record with a consideration of the seriousness of appellant’s crime. The defense pointed out that appellant does not need to be rehabilitated; she is not a danger to society. That may or may not be accurate. Individual offenders have individual characteristics which the trial court can best evaluate, and appellant did kill another human being. Abusive as the victim’s behavior toward her may have been, he was nevertheless entitled to live. The consequences would be unthinkable if all of us chose appellant’s way to rid ourselves of people who mistreat us. The sentencing in this ease is an affirmation that society does not and cannot condone appellant’s action; it reflects the public’s respect and regard for human life and for the law. We therefore see no abuse of discretion in the sentence.
Affirmed.
. Rule 49(b), W.R.Cr.P., provides:
“(b) Plain error — Plain errors or defects affecting substantial rights may be noticed although they were not brought to the attention of the court.”
. Proposed Instruction A:
“The defendant has produced evidence alleging that she acted in self-defense. You are instructed that before the defendant may be convicted of any crime, the State must prove to you beyond a reasonable doubt that the defendant did not act in self-defense.”
Proposed Instruction C:
“The relative physical sizes and ages of the defendant and Lowell Scheikofsky, are factors which you may take into consideration in determining whether the defendant had reasonable grounds to believe and actually did believe that she was in imminent danger of death or serious bodily harm, and that deadly force was necessary to repel such danger.”
Proposed Instruction D:
“If you find that the initial use of deadly force was justified you must not then find that the defendant’s claim of self-defense is negated because several shots were fired or because shots were fired after the apprehended danger was over. A person in *1110imminent peril of death or serious bodily injury, or one who has reasonable grounds to believe she is in such peril, is not expected to have perfect judgment. A person who has reasonable grounds to believe herself to be threatened by an armed person does not have time to reason out every response she should make or to judge precisely how much force she has to use to ensure her safety.”
. Wyo.P.J.I.Cr., § 5.201, Justifiable Homicide in Self-defense, states the law concerning the reasonableness of the defendant’s belief of imminent danger:
“If the defendant had reasonable grounds to believe and actually did believe that he was in imminent danger of death or serious bodily harm from which he could save himself only by using deadly force against his assailant, he had the right to use deadly force in order to defend himself. ‘Deadly force’ means force which is likely to cause death or serious bodily harm.
“The circumstances under which he acted must have been such as to produce in the mind of a reasonably prudent person, similarly situated, the reasonable belief that the other person was about to kill him or do him serious bodily harm. The danger must have been apparent, present and imminent or must have appeared to be so under the circumstances.
“If the defendant believed that he was in imminent danger of death or serious bodily harm, and that deadly force was necessary to repel such danger, and if a reasonable person in a similar situation seeing and knowing the same facts would be justified in believing himself in similar danger, he would be justified in using deadly force in self-defense. He would be justified even though the appearance of danger later proved to be false and there was actually neither purpose on the part of the other person to kill him or do him serious bodily harm nor imminent danger that it would be done, nor actual necessity that deadly force be used in self-defense. If the person so confronted acts in self-defense upon such appearances of danger from honest belief, his right of self-defense is the same whether the danger is real or merely apparent.”
. Instruction No. 12:
“The law places the burden upon the state to prove the defendant is guilty. The law does not require the defendant to prove her innocence. Accordingly, you must assume that the defendant is innocent unless you are convinced beyond a reasonable doubt and from all the evidence in the case that she is guilty. “You should evaluate the evidence admitted in this case and determine the innocence or guilt of the defendant entirely in accordance with these instructions. The test you must use is this: if you have a reasonable doubt as to the truth of any of the claims made by the state, you should find the defendant not guilty. If you have no reasonable doubt as to the truth of any of them you should find the defendant guilty.”
. Instruction No. 2 read:
“The defendant is charged with the crime of second degree murder. The defendant has pleaded not guilty.
“To establish this charge, each of the following must be proved beyond a reasonable doubt.
“1. The crime occurred within Crook County, Wyoming, on or about the 25th day of October, 1980; and
“2. The defendant killed a human being; and
“3. The defendant acted purposely; and
“4. With malice.”
*1112Instruction No. 4 read:
“ ‘With malice’ means the commission of a wrongful act done intentionally without legal justification or excuse. The term ‘malice’ conveys the meaning of hatred, ill will, or hostility toward another and implies a wicked condition of mind.”