What is the test for determining the credibility of a witness in a sexual assault case?

fact could find the defendant guilty beyond a reasonable doubt. [Citation.']" (People v. Story (2009) 45 Cal.4th 1282, 1296.)" '[I]t is the exclusive province of the trial judge or jury to determine the credibility of a witness and the truth or falsity of the facts on which that determination depends. [Citation.] Thus, if the verdict is supported by substantial evidence, we must accord due deference to the trier of fact and not substitute our evaluation of a witness's credibility for that of the fact finder. [Citations.]' [Citation.]" (People v. Ochoa (1993) 6 Cal.4th 1199, 1206.)