The need for certainty about another person can reveal uncertainty about your ability to survive being wrong.

The demand to be sure about someone is often less about them than about you. If you knew you could survive being wrong, misplaced trust would be painful rather than catastrophic, and you would not need guarantees before you could act. The search for certainty is usually a way of asking whether you would be all right if it went badly.

When you are interrogating a relationship for proof, turn the question around. What would happen if this person let you down. If the honest answer is that it would hurt and you would recover, the certainty stops being necessary and the relationship gets to breathe.