The poor guy here likes this girl, but she clearly doesn't feel the same way. Yet she keeps him hoping that she does, for whatever reason it may be; the attention, to get back at someone or maybe for reasons she don't even know herself.
The situation here seems they are sorta seeing each other rather than dating, where the guy is doing all he can for the girl cos he likes her, and he just wants her to like him back. She dosnt quite lead him on, yet she doesn't let him go either.
The guy beleives things are going somewhere but the girl is never interested,. "your hearts been wasted on me". To her this is just nothing, taking waht she can get along the way.