The answer to this question can be found in Chapter 11. Ironically, Godfrey gets his chance to spend some time alone with Nancy when he manages to partially ruin her dress, because it has a long back and his stamping feet had destroyed some of the stitching. Ever the chivalrous knight, Godfrey accompanies Nancy off the dance floor and stays with her, giving them a chance to talk together. This valuable opportunity to "sound her out" reveals that she is not entirely hard and stubborn towards him:
"I think those have the least feeling that act wrong to begin with," said Nancy, sending out a flash in spite of herself. Godfrey was delighted with that little flash, and would have liked to go on and make her quarrel with him; Nancy was so exasperatingly quiet and firm. But she was not indifferent to him yet, though--
Close proximity has yielded its results and given Godfrey the hope that he has been longing for--that Nancy might still care for him and she is not entirely indifferent when thinking of him.