how did you understand he/she was "the right one"??

I think I still don't understand but I decided to give it a chance. Why? Because he wants to get married and I have nothing to loose. I told him that if he thinks I am the one he has to prove that to me in every way he can think out. I can think and wait for the rest of my life for the real one or live my life and take the fullest out of it (taking changes). Why should I be in the way of my own luck? Just because I am too afraid to give it a try? I see it as an other challenge. I will see what will happen.

I don't actually conclude that she was the right one because she is still not my wife. This means that there is still a possibility that we could break up anytime for any reason.