I think we have to enlarge the meaning of "believe." The tendency is that believe=accuracy of what we say and acceptance of what we say. But I think they're very different intents.

I know my T has always accepted what I said. He did not always believe in the accuracy of what I said.

When I first sought out my T, I presented with a delusion. It was extremely real emotionally, based in real actions with demonstrated effects, but the core belief was not objectively accurate.

The emotional belief persisted for several months. Then came a day when I started having doubts about its objective truth. My T allowed my doubts to play out until I reached the conclusion that my belief was, in fact, not real. He admitted then that he'd wondered when I would realize this, as he had far earlier. But he never confronted me because he knew that the delusion was a defense--against what we didn't know yet. I was horrified that I could have been so confused. I cried and told him that I wasn't lying to him for all those months. His face softened, and he quietly said, "FKM, I never thought you were."