There might have been a time, when the breakup was still fresh in her mind, that she had viewed him with nothing but scorn and contempt for the way he'd ended things. Now, however, she realized that despite his methods it really had been for the best. They clearly weren't right for each other, and their relationship's ending was inevitable. Even now Sarah remained generally oblivious to Roy's affections, though, which meant that he didn't quite factor into her reasoning.
She hadn't been lying when she didn't hate him. Even when she'd thought she had, it had really just been bitterness and a little big of teenage immaturity - it was silly to hate someone over a high school breakup. That didn't mean she wanted to be best friends with Vince or anything, but glaring at him in the halls and replying with one-word answers wasn't what she wanted either. "That doesn't surprise me," she said wryly, actually managing to crack a smile.
Of course she shouldn't have expected him to relent, because it was Vince. She could have been stubborn and refused, perhaps even simply turned around and marched back to her apartment, but she didn't have it in her to be that cruel. Instead she was the one who relented, her tense posture relaxing as she looked up at him with the beginnings of an almost helpless laugh on her lips. "Truce. You know I'm not very good at holding a grudge." Some might have thought her weak for it, but the last thing she needed was to create more animosity - especially with Roy and Vince now living in such close proximity.