Aishiteruze Baby★★, Hana to Akuma Recommendations
Both are about a guy who watches over a girl.
in AB it's about a normal guy who watches over his aunt's child. They don't fall in love as girlfriend boyfriend but in HtA they do. Alos in HtA, the guy is a vampire while the girl is a human. Both are really sweet romance stories. If you like one, I'm sure you'll like the other. >.<