he loved her but never promised her of his love as he knew how much deeply she is in love with him and also he knew he won't be able to protect his promise so he never took the risk of telling her how much he loves her
in this way he says that she will be less hurt, if she gets to know that he too loves her she won't move on and make her own beautiful life
"let her be happy without my love" were his last words for her innocent love while "i will always cherish the love i have for him" were her last words for his unknown love