The faithless one

A song was sang in church last Sunday and it went something like this,"I have faith in you". I almost teared at this because it just hit me how little faith I have and how much disbelief is still residing in my heart. I sometimes find myself not believing that God answers prayers. The head knows that He answers prayers in His own time and way and that what we ask for may not be the best options for us, and He will sometimes present us with things other than what we asked for. The head knows all these, yet the heart is always obstinate, not listening nor understanding, nor believing. How does one grow faith and not just knowledge?