Now there are a rare breed (maybe not so rare anymore) that can make up fabrications, and somehow mentally convince themselves they didn't make them up and actually believe them. I've seen no proof of Trump doing this.

Trump has repeatedly claimed that millions of non-citizens voted for Clinton, even after his bogus voter fraud commission disintegrated without finding any evidence to back up his claim.

So either he knows that his claim is false (he’s lying) or he’s convinced himself that it’s true (narcissistic personality disorder).