I pretty much agree with all of ReineD's post and this in particular. I hate my male body and always did even as a child when I no sense of why I did. I thought I was ugly. The photos of the time say otherwise.
In reference to the original premise of the thread. I think I see where you can convince yourself that you're a woman when in fact you are simply a crossdresser. The irony for me is that I spent years convincing myself I was a crossdresser when I was really transgender. As part of that I pursued a quixotic career dream and other displacement activities. Looking back now it was rather comic and it must be said sad.
But in terms of convincing yourself of being something you're not. Well the example is there in the entertainment industry. Many of the better known actors are method actors. They become the person they play. Daniel Day Lewis famously so. I think in many ways one of the catalysts of my own self realisation came when I began to work as an Extra and small acting roles on TV and movies. I found I was a natural, after all I was pretending to be a man all my life. But it was soon obvious that you could easily convince yourself you're the person you play. Dashing through a forest at night while been shot at was terrifying even though it wasn't real. I became angry at a lawyer who was cross examining me. It became real even in the midst of all the paraphernalia of movie sets.
But it was all illusory because I actually don't know what it's like to be shot at or have a lawyer cross examine me. I think I do but I don't and I do think many actors believe they have more of an insight into the lives of the people they play than they do in reality.
So I can see how a CD can take it to the point that they begin to believe they are in fact TG or actually female. There have been cases of people going all the way to transition and then regretting it. They convince themselves to the point where reality and imagination are hard to tell apart. This isn't just the case with CDs. It's there in the whole of society. People turning up on TV talent shows CONVINCED they can sing.
We all do it in one form or another in our lives. Maybe it's the human condition. How we cope with our lives. My life began to fall apart when I lost a lot of convictions and illusions about myself. When I faced into the reality of my TG state. I ended up like PaulaQ, in despair and suicidal. I actually got married as a way of avoiding it and convincing myself I wasn't really TG. Didn't work though.
Reality has a way of destroying conviction.