If I'm on the mark here, it's kind of related to being able to play devil's advocate. There are topics where the same person can decide to make a strong case f

If I'm on the mark here, it's kind of related to being able to play devil's advocate. There are topics where the same person can decide to make a strong case for or a strong case against something, just by focusing on a different set of pros and cons, a different set of values, a different perspective, or focusing on different facts. "Belief" in this context is which of these sets of arguments you find most convincing. One can even make a strong argument for something one doesn't believe in (although I can't recommend it[1]) - I'd call this a "Strong opinion, not held". Instead assuming good faith - you and I are no oracles. Even our strongest arguments will have gaps, things we hadn't considered. Our arguments will sometimes have flaws - incorrect assumptions or other faulty basis we hadn't realized we'd made. It's the cost of being human. It's not so much certainty of belief, but being able to move forward with confidence, and argue for, the best path you can discern - yet aware that even the best of us will be wrong at least some of the time. It's about being able to recognize and turn on a dime - to course correct - when that stronger argument is made for a different path, even if you were damn sure about the one you were on not a moment before. [1] EDIT: Err, arguing only for the side you don't believe in at any rate. Arguing for both sides or explicitly playing devil's advocate if the other party seems to be arguing your own viewpoint sufficiently seems perfectly fine though.