Of course he would claim the opposite of the truth. He has shown himself to be a delusional egomaniac. "The Boy Scouts called me and said it was the best speech they've ever seen!"  Either Trump really believes that, which means he's mentally ill, or he knows it's false but tells the world anyway believing no one will find out it's a lie, which means he's mentally ill, or he knows it's false, knows he will be shown (again) to be a liar, but doesn't care, which means he's mentally ill. Take your pick.