I would really very strongly recommend not updating on an intuitive feeling of “I can trust this guy,” considering that in the counterfactual case (where you could not in fact, trust the guy), you would be equally likely to have that exact feeling!
Fictional support:
Romana: You mean you didn’t believe his story?
The Doctor: No.
Romana: But he had such an honest face.
The Doctor: Romana, you can’t be a successful crook with a dishonest face, can you?
Fictional support:
Doctor Who