Most Helpful Guy
See I hate it when a girl says that, because the ultimate expression of love is self sacrifice and while actions do speak louder then words. There are few actions that can adequately express ones love for someone. And there lies a big risk of trying to hard, or the women just not appreciating the effort because its not the way she wants you to do it or so forth.
Its better to let such actions happen naturally through the course of a relationship without being pressured into doing such actions, as it defeats the purpose of them in the first place. After all what is more meaningful asking someone to prove their love, or them doing it on their own because they want to not because they were asked.
Most Helpful Girl
She just wants you to show more affection, she feels like you don't love her enough, so she just needs proof. It's not hard, just be more affectionate.