Trust me...  

You can because you can't see me. Here's how we decide if someone is trustworthy:

To find out what cues the players were responding to, the researchers filmed the students’ five-minute conversations before the game started. They discovered that four specific gestures predicted when a person was less trustworthy: leaning away from someone; crossing arms in a blocking fashion; touching, rubbing or grasping hands together; and touching oneself on the face, abdomen or elsewhere. These cues were not predictive by themselves; they predicted untrustworthiness only in combination. [More]

Therefore I should tell you I'm not doing any of those things.

(I'm scratching something.)