Thank you to everyone who replied. I'll try to respond to the questions as best I can.
I guess when I say 100% trust him, it's about being able to trust that no matter what I say or talk to him about that he won't do what my previous T did. She made me believe that ANYTHING I needed to say or tell her would be ok and "honored", but in the end, that wasn't true. And it wasn't about any sort of threat or danger to herself or others or anything like that. When I said I was naive to think that I could "only" talk about eating issues, I just meant that I was silly to think that my problems with binge and compulsive eating were not tied into my other problems (depression, extreme anxiety, trust issues (that were there from childhood trauma), etc.
I think instead of just trying to convince me over and over, current T is trying to help me trust and feel confident in myself that if he (or anyone else I love or care about) goes away for some unforeseen reason (he gets into an accident, dies, etc.), that I would be able to handle that, and it wouldn't completely paralyze me in grief. I like this idea of strengthening my confidence in being ok if someone really important to me leaves for whatever reason. It's complicated by the traumatic experience I had at a state psychiatric hospital during a severe depressive episode that occurred about 10 months after T-1 abandonment. I'm terrified of getting back to that point. I have such a strong fear of abandonment that I don't allow myself to get close to anyone. The result of that is that I'm incredibly lonely but also incredibly fearful of letting myself love anyone or accept love in return. That is what I want to change. I don't want to be so terrified of emotionally intimate relationships.
He has helped me figure out triggers for emotional / compulsive eating and ways to help myself get out of the cycle when it starts, stress management techniques, etc. The eating problems are one piece of a much larger pie that includes a lot of family relationship issues, work stress management, history of emotional neglect / sexual abuse (he doesn't know about abuse yet), etc. I do feel like he is extremely respectful of me and my needs. He has never done anything that gives me a reason to suspect he is anything but a highly ethical and completely professional therapist. I guess that's why it's so frustrating for me that I can't just get past those previous issues. But really, that incident was only a retraumatization of my childhood emotional neglect and abandonment, which current T says is part of what is making this so difficult for me to overcome.
Thank you again to everyone. I really appreciate all the insight and suggestions from you all.