What does it mean when someone sends you a song that makes you happy?

This means to express strong joy and excitement.

A person gives you the song "Easy with Beauty". He specially chose it for you. He thinks this song can convey his love and joy for you. He wants to express his special feelings for you through this song, or he wants to share his happiness and excitement with you. This method is his personal expression and he hopes to convey his emotions through music.