He thought that his pal PUtin had smoothed everything over for him, he didn't have to get the nuclear information, Kim would give him everything he wanted if he just "went along". He's so delusional and such a narcissistic fool, he got totally played. I am just so grateful he didn't go ahead and do something really really stupid in exchange for nothing. It certainly could have been a lot worse. Of course, the whole thing is a total unforced error by trumpty. His delusions of grandeur from a much desired Nobel prize were very dangerous, but luckily a hint of reality hit him and he walked away from the stupid shit show.