The best conmen are the ones who fool themselves. In a sense, his sincerity is beside the point. But if he really was sincere, why did he title his book The 4HWW unless it was to sensationalize his work, and draw more attention to himself, and make more money. Tim has other aspects of a conman, and it's not just the way he practices martial arts. Rebecca Mead wrote a great profile about him here:

http://www.newyorker.com/magazine/2011/09/05/better-faster-s...