I think trust is necessary before discussing something like suicidal thoughts. For me, the first appointment, or even the 10th would not have been the time to do that.
And sometimes no matter how directly a client tells the therapist something - they do not hear, pay attention or believe the client. So I don't think it is always a problem that the client expects a therapist to be a mind reader. Plus, with the therapist and me, it is a good thing she is not a mind reader.