Oi duen liu sin

the movie also is about destiny and whether or not fate can be changed if we know the ultimate result of the choices we make. Even though the female lead knew what was going to happen, she relented and perhaps even hastened the outcome by turning a cold shoulder to her best friend and the one she admired, instead of trying a different tact to change the outcome (future). One thing I don't understand is why did the male lead seem so dejected after learning her decision that the one she admired would not work out? I mean after all, if she did pursue him and was successful, he would have a different mother. Whats exactly to be upset about? And why did he not do something when he actually encountered her in the university? And can we interpret by the way she moped down the hall that her life turned out bad/sad? The comment was dropped in the movie that she changed universities when the male lead entered the same college; obviously alluding to the fact she was keeping track of him, even after 23 years had passed since he last talked to her. I need answers people!