The answer is easy. It's as easy as breathing. Saying it out loud is another matter altogether. He'd explained it, once, under some compulsion, and hadn't been keen on trying to explain those particulars to Astarion. What might seem as deep contemplation as to the root cause of his belief is really just trying to figure out what to even say to her.

"I get doubts. On the particulars. Believe me, I've had my doubts." And maybe she can guess that his time with the Templars--and the time out of the Templars--might be part of that.

He licks his lips, looking less at her and more at the fire. Maybe with someone else, he'd put up more of a front. Say something sly, something that isn't technically a lie and then adjust the topic. He'll be uncomfortable, vulnerable, when it's just her.

"It's very personal and dear to me. If you ask me again," with some deliberate weight, "if you really want to know, I'll tell you, because I trust you. But I know it's going to make me sound crazy. And I don't want you to think that of me."

Maybe it won't sound too crazy, to her. When compared with the things she's seen, the things she can now do. And heresy isn't a concept she'll ever be concerned with. But a lifetime of learning that saying the wrong thing can get one ostracized or much, much worse is hard to unlearn. He was a quick study on the kind of statements that Sisters don't like hearing from troublesome wannabe Templar initiates.

Tend to be the kind of things most people don't like to hear, either.