Natasha wasn't someone who surprised very easily; Bucky's abrupt apology succeeded in doing just that. Partly for the abruptness of it, yes, but some of it down to the fact that she couldn't place exactly what it was that he was apologizing for. It took her a minute to walk back to the last conversation they'd had. She had been so deeply, darkly irritated with him, some of which he had brought entirely on himself and some of which, when her more rational mind had come back into play, was a little unfair. It almost made her smile, really, that this was the part of the conversation he'd chosen to fixate on.
"That's not why I did it. The books were a fun thing for us," she promised him, aware of her use of the past tense. She didn't see any real need to correct that, though; many things were past tense, now. "You didn't overstep a line with any of them, Bucky. If I was harsh about that the last time we spoke, it was only because it wasn't really a moment when I was interested in being distracted from what was going on. And I wasn't interested in distracting you, either. I was upset with you and I didn't...I guess I didn't really feel like trying to do something that I knew would make you feel better, not right then."
She forgot, sometimes, that offhand comments she made about sex could have ripple effects that she hadn't thought about. She forgot what it looked like to other people, sometimes. And while she wouldn't say she was sorry that now she felt absolutely free to turn down invitations (that weren't really invitations, that never had been) that came from Stane's office, it was something that she'd mostly numbed to. Enough that she could joke about it, sometimes, and she'd forgotten that it didn't always read to other people as jokes.
Especially not someone like Bucky, who could barely stand to be touched as it was.
She wondered when she'd stopped calling him 'James', for a moment, then decided it didn't actually matter, so it was a stupid thing to wonder.
Natasha smiled, a little, and it was real enough. "Your slate's clean with me," she told him. That was a nice thing to be able to tell someone, no loose ends. "There won't be anything you have to have regrets about on my account, if it all ends up going as badly as everyone at Tony's seems to think it will."