Subsconscious release of secret or hidden information may release guilt!
Among other things, the conscious or subconscious release of secret or hidden information may release guilt or shame! And quite naturally, from a conscious perspective, one may not wish to talk about such things, they may be considered private, or skeletons in the closet etc. However, if they are somehow implicated in the issue to which you seek a solution, they are very often better out than in. It is only when these aspects of your issue are open to discussion, that the likelihood of a solution can be found. That said, once trust is established, these things often tend to come up openly in discussion. Some surface as memories, sometimes known to the client, sometimes a complete surprise to them. But essentially they are the product of a collaborative approach by the therapist to assist the client find the cause of their issue and onward from that; the solution!
When it comes to other matters, e.g. secret information or information irrelevant to the issues at hand, the hypnotherapist has little or no interest in discovering such information. In essence you are no more likely to divulge anything under hypnosis, that you wouldn't anywhere else. The comfort you have, however, is knowing that what is said in the room; stays in the room and that's a promise!