In a letter to his friend and confidante Mr. Deighton, Sanford relates his successful efforts to seduce Eliza despite already being married. In particular, he boasts of making himself cry in order to persuade Eliza of his devotion and regret over marrying Nancy. Describing this behavior, Sanford uses a simile to compare himself to a woman:
Indeed, Charles, I never knew I had so much sensibility before! Why, I was as much a woman as the very weakest of the sex!
In this passage, Sanford compares himself not just to women in general but to "the very weakest of the sex." His remark draws on contemporary cultural norms that associated crying and other displays of emotion with femininity, and the widespread belief that such behaviors were shameful for men.
This simile immediately highlights Sanford's callousness and malicious intentions toward Eliza. While she sees his tears as a genuine display of emotion, he confesses to Mr. Deighton that he's manipulating her feelings to entice her into an affair which will be ruinous for her reputation and marriage prospects. Moreover, even as he admits to taking advantage of Eliza, he denigrates women as a whole, saying he believes them to be inherently weaker than men. While Eliza and Sanford initially seem similar due to their high spirits and flirtatious habits, moments like this draw a sharp contrast between Eliza's open, trusting demeanor and Sanford's predatory character.
More broadly, this simile subverts the sharp distinctions between masculinity and femininity enforced in the early American society Foster depicts. The characters in this novel see gender as fixed and unchanging, and believe that people naturally possess certain traits by virtue of being born as a man or woman. For example, women are supposed to be modest and chaste; if they behave otherwise, as Eliza does, other characters reprimand them for failing to conform to expectations for their gender. Yet although Sanford intends only to make a sexist joke, he implicitly suggests that men and women can easily adopt behaviors associated with the opposite sex, therefore undermining his society's rigid gender norms. Although Foster clearly intends the reader to revile Sanford, this passage bolsters her case against sexist expectations of female behavior by calling the entire concept of gender into question.
