I’ve been asking myself this question -— How do you prove rape vs consensual sex?
You can’t.
Which means we make the decision based on which of the parties tells a better story.
Somewhat of a problem when various of the parties are professional actors.
Actually it’s a problem anytime. Unless someone can explain a way to reach an honest verdict of “guilty beyond a reasonable doubt” based solely on one person’s testimony that is directly contradicted by another person’s.
You can't. But, if you can widely publicise your accusations and get some more "victims" to join your cause, you can overwhelm the target (the very wealthy Cosby in this case) and do a class action suit in hopes that he'll pay you off to get you off his back.
That is one reason there are Statutes of Limitations.