Depends on what you consider proof. I mean, the man himself said that he gropes women because he can. He said this in a private conversation without any knowledge of being recorded. I have not reason not believe his claim. Maybe he was blustering but I don't believe it. He's claimed to walk in on beauty contestants while they are naked. He didn't mind when Howard Stern referred to his daughter as a "piece of ass". The totality of what we know about Donald Trump is such that it takes a lot of mental gymnastics to believe that he has never groped women.