Since this is a love song, "... I never really had a doubt" means that she never had any concern or lack of confidence about the man finding a way to become close to her (or to fall in love with her, perhaps).
"... I got my angel now" means "I got my lover/man now", the "angel" in this song refers to her lover/the man she is singing about. She says she is "standing in the light of his halo" because she is in love and he is like an angel to her.
(Although I probably wouldn't consider Jay-Z an angel myself with his past!)
- For Teachers