On the subject of false allegations...?

I think it should be fairly obvious that if a woman is found to have falsely accuse a man of , then she should suffer the full consequences of her actions--up to and including jail time. My issue is, how do we know if it was a false allegation? If it can be proven without a shadow of a doubt that is was false, then punish her. Its a crime to falsify a report and it is an attempt to ruin another individuals life. So there should be dire consequences. However, if the allegations are simply shady or unsubstantiated, then clearly there can be no punishment. This does mean that it will be hard to prove one is making a false allegation. Many cases come down to "he said, she said." Proving a did or did not happen is incredibly hard. If it can not be proven, that doesn't mean it was a "false allegation."