Don't need to. You wouldn't change your tune anyway if they did.
I don't need to prove my character to a random person.
If you catch me in a lie or lowballing then simply file it away to bring up in the future. Don't leave out words and misquote me in an attempt to twist what I'm saying. The fact that you do that proves that you agree with me but don't like the fact that I'm right. Otherwise you would simply let the truth stand on its own without a need to manipulate it.