What is the test for a jury to convict a defendant in a sexual assault case?

Defendant suggests the trial court should have tailored a limiting instruction such as that used in People v. Fitch, supra, 55 Cal.App.4th at pp. 182-183, footnote 4, which told the jury: "You may not convict [the defendant] merely because you believe he committed a--another offense or because you believe he has a character trait that tends to predispose him to committing the charged offense. [] The question before you is whether the defendant is guilty of the crime charged in this case, not whether he is guilty of any other offense. [] You may return a verdict of guilty only if you are convinced beyond a reasonable doubt that he committed the offense charged against him in this case. . . ."