He returned again, offering to make her a lady-in-waiting, and then to dismiss the countess and marry her. The last offer would not have moved her even if she had wanted to be the countess, because the countess had helped her when her grandmother was ill.
The man returned, proposing to make her a lady-in-waiting and then to dismiss the countess and marry her. This final offer wouldn't have swayed her even if she desired to be the countess because of the countess's kindness during her grandmother's illness.