River

River

Tough choice, but I go with River.
River realizes the depth of the sacrifices her brother has made for her. She is a burden to him most of the time and is heartbroken because simply live his life. Simon refutes this over and over to River that he has no regrets about saving her and that she is everything he needs to be content.

She tried to 'fix' Shepherd Book's bible due to her finding some of the biblical stories illogical.

Her way of communication is almost lyrical, always deeper than it appears, consisting mostly of cryptic metaphors and never simple

It is possible that the time spent with her new family on the ship has lessened the effects of her trauma. When they shoot the shit and tension is low, she's at ease.