Marlow in this comedy by Goldsmith is certainly a very strange character. On the one hand, he is unable to communicate meaningfully with a member of the opposite sex if they are from his own class. However, he is more than able to express himself if he is talking to a servingwoman or a female servant. When he talks with his friend, Hastings, about this phenomenon, he explains that he has not learnt what Hastings describes as "a requisite share of assurance," or confidence and self-belief, that he has never had the opportunity to learn that with people of his own class:
My life has been chiefly spent in a college or an inn, in seclusion from that lovely part of the creation that chiefly teach men confidence. I don't know that I was every familiarly acquainted with a single modest woman--except my mother--but among females of another class, you know--
Marlow's strange behaviour that is so different depending on the class of the woman he is with therefore is a result of his strange upbringing and the way that he was always on the move, and that he never had the opportunity to get to know women of his own class. The final "you know" of the above quote suggests that the "other class" of females he is talking about are actually women who are willing for him to have his way with them. This of course results in hilarious comedy when Marlow mistakes Kate for such a woman.