The information you could reveal is not automatically information your honesty requires you to reveal.

Honesty is about not deceiving, which is a narrower duty than telling everything you know. You can decline to share an opinion, a history, a diagnosis, a private matter belonging to somebody else, and still be entirely truthful. Confusing the two turns disclosure into a test of character and makes people feel that privacy is a form of lying. Some information is simply not owed, and withholding it is not a compromise.

Before volunteering something difficult, ask whether it is needed or only available. If the answer is that it would mainly relieve you to say it, that is worth knowing before you speak.