One day you will cry for me like I cried for you

One day a boy gave a cheat to her girlfriend He said, " open it when i die ".
Girl Thought it was nothing but a joke so she asked why. The boy replied I like your smile, just keep smilling. The girl ignored and after few years of realationship the girl dumped him. But the boy was not bothered about it so he said can we friends again. The girl said okay, cool. Some years later he found that the girl was again in a relationship. He approached her whole heartedly and saw that the smile was missing. He asked what's the matter, she replied her raelationship was in trouble he used her and dumped her, She was crying and at that same moment she saw that he was smilling at her, she got angry and slapped him. The boy turned away, suddenly she realised that he was in the same way as now she is going thorugh. She opened her dieary and found a cheat she opened and cried. Next day she wanted to meet him. Years past, but he never turned up, then she realised that what was written in the cheat was the truth.
"Keep smilling everytime i see you everytime I hold you, I swear I will dir if I see you crying. Don't worry you will be in always in my heart"