Read The Hidden Saintess Manga:
Many years ago, there lived a knight who loved a saintess. However, wanting to not hurt the saintess who wasn't allowed to have personal feelings, he made sure to keep a safe distance from her. Eventually, the saintess died in his arms and the devastated knight swore, with bitter anguish, 'If you get a chance at another life, I'll make sure that you will no longer live as a saintess.' After a long 300 ye more.. ars, the saintess was reborn. Will their wishes finally come true in this life?