His effort was all what she asked. For all the time, she puts a lot of efforts to make him happy. But as for her, she didn't sense any effort he puts into their relationship. She was so tired making efforts to make him stay. She never wanted him to leave. All she wants is just for him to love her with all his heart. But then, he treated her like trash. Like she was not his girlfriend. She feels like he's taking her for granted. He never looks at her with all his heart. He never treasures her heart. He never did anything that makes her happy. So as for her, why must she stay? There is no reason that left for her to stay. She left him with no goodbye. She had no choice left. Sorry, but she had to.