To build a successful career as a politician you need to be good at lying. At least in the vast majority of cases, there are always outliers.
Now Trump never built a successful career as a politician. In the "career" that led him to politics, his utterances were not subject to anywhere near as much scrutiny. He had lawyers to go over anything he signed and could be held accountable for. But in terms of what came out of his mouth, he could basically make it up as he went along.
I'm like Cal. I prefer someone like Trump who is very bad at lying to someone who is very good at lying. I prefer someone like Trump who says what he is thinking rather than someone who is adept at saying one thing, signalling another, and meaning something else again.