Does a client need to believe in hypnosis?

About ten years ago I had about thirty NLP sessions with 3 or 4 different people. Most of the sessions were quite powerful but they never resulted in the changes I was looking for.

Recently I read that belief is an important factor in one’s success with therapy. Although I was hopeful I would not say I strongly believed that NLP would work.

So now I’m considering hypnosis and wondering how important the factor of belief is.