The parade of European figures, especially, who imagined they could charm that stupid American president and get something out of him was quite pathetic to watch. I don't want to get too deep into clinical diagnosis territory, but if you think you can charm a man like Trump, then you have never known a man like Trump. Or not taken any lessons when you have.
There are some people Trump is genuinely charmed by, at least temporarily. But he eventually turns on them, too. Everyone else is just sucker he's playing a dominance game with.
One secret to the success of President Deals is he has never felt bound by any of those deals. His word means shit.
Give him an inch and he knows you're an easy mark.