Allan Piper at Now This Politics has a great video up describing why we must believe women who say they've been sexually assaulted. In it, Piper points out that this isn't because women are more honest or trustworthy than men, but because the odds are that women WILL be assaulted sometime in their lifetime. Knowing that at least a quarter of women will be assaulted should make men more apt to believe a woman when she comes forward. Piper also points out that there's no incentive for a woman to report her attack given that she will face the most consequences, from the invasive rape kit that will go untested to the lack of justice to her own blaming, shaming and even violent threats from people angry with her for coming forward.
Piper also says that there are pretty much no consequences for most men who face rape accusations. They become presidents and Supreme Court justices. When they actually do stand trial, only a handful serve time in jail, and even those are out in months. Judges don't want to "ruin the lives" of men accused of rape and think that losing a job is enough punishment. There are examples every day of men who get away with assault with little to no consequences and women who are blamed for their own attacks.
Just what will it take for men to believe women?