I encounter this often teaching English as a foreign language. Language is not science, but there are certain governing rules and structure to organize and contain its ever-growing sprawl. Students will ask questions seeking definitive answers or wonder why this is like this but isn’t like that. I don’t have all the answers, though it’s important to be authoritative, because not only are you teaching people how to communicate using unfamiliar sounds and patterns, because you’re also a psychiatrist to maintain confidence and enthusiasm for a task that can be a slog. In cases where I am unsure, or maybe even wrong, I hedge and say, “I’m not 100% on this point, so I’m willing to hear arguments why you think it’s that.” Then, later I can check to confirm.