This worry usually comes from picturing hypnosis like an interrogation where everything just spills out. It's actually the opposite: during the trance itself, you normally don't talk at all. That's because the subconscious doesn't communicate in words — any talking runs through the conscious mind, which is exactly what we're setting aside during hypnosis.
What actually gets said in a session
Talking happens mainly in the conversation before and after — that's where we discuss your concern, and you decide yourself how much detail to give. During the trance itself, I do the talking, not you: I guide you through the relaxation and the suggestions with my voice. At most, you give back a small signal — a light nod, or an agreed hand signal, if I specifically ask for one. Extended, uncontrolled talking, the kind you see in movies, simply doesn't happen in a normal hypnosis session.
Why the "interrogation" idea is a misunderstanding
That idea usually comes from stage hypnosis or films where someone in trance suddenly confesses everything. For that to happen at all, your conscious mind would have to actively participate and form sentences — exactly what steps back during trance. Even if you do speak in deeper trance, for certain therapeutic techniques where I deliberately ask you to describe something, you stay responsive the whole time and decide what you say. There's no mechanism by which something "slips out" that you didn't want to say.
Whatever you do tell me in our conversation before or after is protected by professional confidentiality, the same as in any therapy. You decide how much you share — hypnosis itself doesn't "pull" anything out of you.