I would say "Immortal Technique f. Jean Grae- You Never Know"

It's about a girl every1 wants & a guy who falls for her
and he admits his feelings to her but all she could do was cry
so he left sight........

Well he got locked up & got out he went to the girl's house
he talked to her mom fo a while & he asked about her daughter......

Finally the mom told him there was a note for him.... And he
find's out she died because she had a blood transfusion and got
HIV from it.... And the last line is..................................

"you never really know what you got, until it's gone"

And that is truly sad.......