Lies need support. The truth doesn’t.

So if you want to see how much someone believes in the things they say, look at how much they defend and fight for it. If they must protect it, it’s a weak lie that has to be maintained by them. If they don’t care and about disagreement or any sort of oppositional viewpoint, it’s because it’s their own personal truth that doesn’t require any effort on their part to be strong, it’s self sustaining. It’s an absolute value to them, so it doesn’t matter what the world thinks of it.