[she stops walking, gently tugging his hand so he'll stop, too. standing to face him, though she doesn't have any need to force him to look at her.]
If you were to leave, I would still not wish to be with anyone else. Even if that happens, I will not regret choosing you. [her smile is gone, her voice more solid -- this is not a commitment she's taking lightly.] I would rather cherish the time we have together to the fullest than look back and wish I had.