According to Jared Kushner, Trump doesn't always believe what he says. For example on Trump's birtherism stance, "he doesn't really believe it, he knows Republicans are stupid and will buy into it."

A friend of Trump's noted, "he'd lie to you about what time of day it is just for the practice," this from a FRIEND. 

https://twitter.com/i/web/status/868893815490445312