This interaction between friends - Lenny Kravitz and Denzel Washington on "The Late Show with David Letterman", provides a great teaching example on the body language of witnessing deception and sincerity. Kravitz is recounting the movies featuring Washington that the two watched on a boat of the coast of Italy. Most people probably don't believe Kravitz when he says, ".... I got him to watch - all of his movies. We sat on that boat ....." (Did you catch the telling pause just before he says, "... all ...", during 1:19? What other verbal indicators of deception did you hear?).
Here it is the witnessing of deception (What else can it indicate?).
Note the dramatically increased blinking frequency Denzel exhibits for a few seconds before and after this moment (1:29 - 1:34). What other nonverbals support Denzel is being sincere and witnessing a lie?
A nose rub/nose touch a moment later (during 1:34 - 1:36) is another highly reliable portion of this deception-witnessing cluster.
It is a profoundly important point to make - that even though Denzel Washington is an two-time Academy Award winning actor, when he is "being Denzel", he is subject to all the same nonverbal tells as those whom are unschooled in acting. Despite all his experience and expertise - he can't suppress them.
If Denzel were the one who was telling a fib, in what manner would his body language differ?
Nonverbal Communication Analysis No. 2961: KTVA Reporter Quits on-air, Drops F-Bomb and Reveals Herself as Owner of Alaska Cannabis Club
Nonverbal Communication Analysis No. 2665: Nick Saban's "Tongue in Cheek" Body Language - What Does It Mean?
Nonverbal Communication Analysis No. 2745: Vladimir Putin's Deception regarding Crimea
Negotiation Secret # 29: Eye Rub When Someone Else is Speaking - Angela doubts Vladimir
Nonverbal Communication Analysis No. 2511: Barack Obama & Vladimir Putin Handshake at 2013 G20 Meeting
Nonverbal Communication Analysis No. 2519: Vladimir Putin Speaks Syria, Chemical Weapons and Disarmament - Body Language just after his New York Times Op-Ed
Nonverbal Communication Analysis No. 2750: Oscar Pistorius, Reeva Steenkamp and Lies - Body Language