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

The fundamental rule for making a finding of guilt or innocence based on an assessment of evidence is set out in R v. W. (D.) [D.W.], 1991 CanLII 93 (SCC), [1991] 1 S.C.R. 742 (S.C.C.), Cory J. stated at paragraph 28: Ideally, appropriate instructions on the issue of credibility should be given, not only during the main charge, but on any recharge. A trial judge might well instruct the jury on the question of credibility along these lines: First, if you believe the evidence of the accused, obviously you must acquit. Second, if you do not believe the testimony of the accused but you are left in reasonable doubt by it, you must acquit. Third, even if you are not left in doubt by the evidence of the accused, you must ask yourself whether, on the basis of the evidence which you do accept, you are convinced beyond a reasonable doubt by that evidence of the guilt of the accused.