Authors:

I have a friend who is an excellent liar. His secret: Believe the lie yourself when you're telling it.

Jack Heffron (2012). “The Writer's Idea Book 10th Anniversary Edition: How to Develop Great Ideas for Fiction, Nonfiction, Poetry, and Screenplays”, p.100, Writer's Digest Books
I have a friend who is an excellent liar. His secret: Believe the lie yourself when you're telling it.