When he saw Su Jianan ,his mind flashed with the image of small girl named Ah Jia ( Su Jianan nickname ).
As he is a cold person, no girls will talk to him not to mention play with him when he was small,but this one girl once mentioned that she is his fiancée and tricked him into playing with her. He is smart but how did he got tricked by Ah JIA.. That morning he was gloomy as he was assigned to do an science experiment with another girl (TINA) and to make him smile his grandfather said "smile Ah Cheng your future wife is coming today, don't scare her with that scary expression on your face" the gloomy face Ah Cheng didn't notice that his grandfather laughed after that (as it was a joke)...AND THAT'S HOW OUR LITTLE GENIUSE AH CHENG WAS TRICKED BY LITTE AH JIA.
He smiled unconsciously when he remembered the wrinkled face of the small girl full of tears when she held his hand tightly saying "Ah Cheng buhubuuhbuhu I'm going to France tomorrow ,I wont be able to play with you again BUHUBUBHU". She took his pinky finger and wrap it around hers while saying "Promise me we will marry when I come back again so that I can wrap you to bring you back to play with me there the next time I come here ". Only when the promise was made did she leave.
But his smile disappeared when he remember that he need to marry her.