Talking to the Rabbi

I've finally decided to just talk to the Rabbi about working on a conversion. I know the question's going to come up, probably within the first MINUTE, "Why?". My wife wants to know too, and so I've held off going further without an answer that isn't self-serving or so fluffy-bunny-feel-good as to be meaningless. And I can't really explain why, either. To myself, I have this feeling inside, a yearning, if you will. But explaining it is... very non-trivial.