This puzzles me. Why do you believe or get reassurance from what a therapist tells you if you would not believe it if you said it to yourself? Or why believe them in general? Why give them power? Why do you think them righter than you or others are?
I am struck by how many like it when the therapist tells them they are good or okay or compliments them whatever. Or when the therapist gives advice. Or when one of them thinks they are modeling something for a client. Why do you think the therapist is the correct thing follow or be reassured by rather than yourself?
If not belief, but reassurance- again- why be reassured by a therapist? How does it work differently than just reassuring yourself?