What kind of girl is Ava?
As her brother, Sam feels he has some right to describe her. Her beauty and her figure are the most superficial aspects. What Sam really values are her intelligence, her kindness, and her obedience.
She's truly smart, always has been. She never caused any worries with her studies, and now she's even earned a scholarship through swimming.
She's very kind. Sam still remembers how she mourned a frozen stray cat for days, and he knows she's never harbored any resentment towards her biological parents. She naively says, "Maybe they had their difficulties too. After all, who would want to give up their own child?"
She's a child too kind to believe in many dark possibilities.
Truly naive.
She's also very obedient. In this family, she knew early on that she wasn't biologically related, but she never made it a problem for anyone. She cleverly knew that treating everyone like true family was the least troublesome way to live.