So, how do I move on. Everyone just says, "Live life to the fullest.", but that way is sinful.
How is that sinful? Living life to the fullest doesn't mean drinking, partying, sleeping around, etc... It means to get out there and experience life. To go places, do things, meet people, try new experiences. It's a way of saying 'stop sitting and dwelling on what you can't have, instead go and find out what else is out there'. And it can be done while still living a Godly life.
Bottom line is this girl doesn't want to be with you. If you love her so much then respect that and leave her alone. Right now you aren't loving her by pushing for what you want. True love is sacrifice. Unconditional love means putting yourself aside, no matter how much it hurts, so they can be happy. If this is not what you are doing, then you are loving conditionally.
Remove yourself from this girls life. If, one day, she changes her mind, then maybe she will come back. And maybe she will move on and you'll never hear from her again. Either way it doesn't mean you have to sit around waiting. Go live your life like she's never coming back.