I know that feeling, and sometimes it can be hard to be open when I am afraid of being manipulative. But in my case sometimes I am also scared of being manipulated into believing something about myself that I am not sure is true. Maybe this uncertainty is the key to the problem, and can be helped by stating things that you know in your heart are true about yourself. To get away from the fears and the twisted picture. Maybe. I could be totally wrong about that. But I think I got what is your point.