The most important character in this excellent comedy by Goldsmith is Marlow. This is because he is the one and only character who is willing to make the decision to marry based on nothing except his emotions. When he "courts" Kate, whom he believes to be nothing more than a barmaid, he gradually comes to fall in love with her, and when pressed by her in Act V, declares that love, saying that he will marry her no matter what her connections and her lack of a dowry. Note what he says:
By heavens, madam, fortune was ever my smallest consideration. Your beauty at first caught my eye; for wh could see that without emotion? But every moment that I converse with you, steals in some new grace, heightens the picture, and gives it stronger expression. What at first seemed rustic plainness, now appears refined simplicity. What seemed forward assurance, now strikes me as the result of courageous innocence and conscious virtue.
There is of course an irony in this speech, as Marlow sees Kate for the dignified well-brought up lady that she actually is, yet what distinguishes Marlow from everybody else is that he is not swayed by money or by connections. An important theme in this play is marriage and the way that Goldsmith satirises it to be the social contract that it was in his day rather than anything to do with emotions. Note how reluctant Constantine is to marry without her jewels. By contrast, Marlow is willing to marry a barmaid because of his emotions alone, which makes him the most important character simply because he is so honest. In a play that is all about hypocrisy and appearances vs. reality, honesty is a virtue indeed.