Are you kidding? He's a sleazy salesman. He's been a sleazy salesman all his life. He gets paid to lie. His success is based on how much and how well he lies.
He's gotten to the point where he doesn't even realize he's lying. To him, lying and telling the truth has no meaning. He says whatever he can to achieve his desired results. Just look at his history.
He said President Obama was born in Kenya. Then he said he was born in the US.
He said President Obama didn't say "Merry Christmas".
He said President Obama wiretapped his campaign office.
He said he was going to build a wall and Mexico was going to pay for it.
I could go on and on but hopefully, you stupid Trump-ass-kissers will get the idea.