"I don't think it'll work..."
Stress in her voice, panic even. As though, even if it were true, that fact would somehow be a negative reflection on her, and there would blame due to her for not happening to own a car large enough to hold that particular box.
You put the seats down and it fits easily.
So that, all afternoon, as she repeats again and again, "I really thought it wasn't going to work," you start to feel more and more sad on her behalf.