That was very bittersweet for both of them. He likes her, a lot. But she's terrified. He's scared to death of the idea of losing her friendship, but, she's frightened by the idea of getting too close to anyone, quite yet anyhow. Being raised by a family who had to tell her the truth, that she'd been built to be a slave, and them having to find ways to teach her to fight against those instincts that her makers had put into her, and others that were not so kind trying to grab her constantly simply because she IS an uplift and, in their minds, not a free-thinking individual, I can understand why it frightened her. Sure she grew up in a loving family, free and away from what she could've truly ended up suffering, but she didn't grow up completely undamaged or unscathed by the truth.