Your question you pose me is really “how do you stop a vindictive liar from getting what they want?” Clearly even the CIA can’t answer this, case in point Edward Snowden. Part of living in a free society is that people are free to be evil too — justice comes after the fact, not before.
Then you can either be paranoid and decide that you’ll never work with someone you think may ever slight you, which can be anyone if we’re taking your logic all the way and recognize that sexual assault allegations by women are not the only thing that can ruin a man’s career, and that evil men can have just as much incentive to wreck someone’s career as a woman. Or you can decide to work in an environment that doesn’t breed toxicity and doesn’t provide such heavy incentives to ruin someone’s career. Bad things can still happen to good people without it being their fault, but that’s what makes them good people.
Also, I can 100% assure you that you have no idea about the sex lives of college students, and I ask that you please don’t believe the ignorant opinions sections of WSJ or Fox that spew nonsense about life on college campuses.
Let me ask you one more thing (although I’m sure you’ll dance around the question): who suffers more and why, a man who gets fired from a job over false accusations, or a woman who gets physically raped and no one, not friends not police, believe her?