These questions about trust are normal in every important relationship in life. There are no guarantees - people can change, or successfully lie to us. It's just a learning experience.

What's that old saying? Trust, but verify.

I don't mean to sound cynical - I do think that having been through what you did with your ex-therapist, you will be better attuned to any danger signs from this one. And I get the impression from your previous posts on this one that this is a far more equitable relationship in which you feel free to voice your concerns and discuss them. That's the learning kicking in.