Now he's saying that "It goes into effect when I want it to. This is my option." and waving a seemingly blank, folded piece of paper around that he keeps in his pocket, claiming it holds the secret agreement. Which is it? How much would it take for you to accept he was lying to save face, other than his directly admitting it?

This is exactly what he did with the piles of unlabeled folders containing blank sheets of paper that he wouldn't let reporters look at while claiming it was the paperwork for putting his business in a supposedly-blind trust run by his kids. It's exactly what he did when he pretended to be his own publicist to puff himself up to reporters. He's lying right to your face and hoping you'll believe him.