Zack was the first person who had given her the feeling that she mattered for something in her life. He had protected her when she needed him the most.
And he let her be willful and spoilt and bratty which were all so foreign feelings for her but all the more pleasant than she ever imagined. He never once complained as to how she must be well behaved and not bring shame to them for the association. She needn't be well mannered… she needn't follow a set of rules… she can just be herself around him.
While all her own mother had ever cared about was how not to lose her face in front of her viper like friends because of her. After all, that was the whole reason why she was shipped off to some godforsaken place when she did not even have the slightest idea of what it meant to survive alone in a country she barely knew. All because her grades were pathetic and her mom can't show her face to others.