The Rise of the Goblin* has gotten me so jaded that I don't think anything would happen even if this turned out to be 100% true. Even if there was video! I think millions of vocal Trump people would just say, "It's his private life!" and "This isn't proof any real wrong-doing!" and "At least he's not black!" I think it would be a momentary embarrassment for him, and then the country would go back to "normal."
*You can have the band name!