A sincerity claim. The person is signalling that what they are saying comes from them, personally.

Honest when the gesture appears unprompted and lingers briefly. Suspect when it is performed deliberately at the start of a sentence designed to be believed (“I swear to you…”). Pair with the speaker’s eye behaviour and blink rate to read which it is.

A heart-clutch in distress (sudden, sharp, accompanied by an inward breath).