After learning that neither Jack nor Algernon is really called Ernest, Gwendolen and Cecily, respectively, argue that the men's "Christian names are still an insuperable barrier." Each woman has always dreamed of falling in love with and marrying a man named Ernest, and so neither one can now accept the actual Christian name of the man each claims to love. Lady Bracknell approves of Algernon's engagement to Cecily because Cecily is incredibly rich. She is ready to force him to leave until Jack mentions that Cecily has a fortune of "a hundred and thirty thousand pounds," and Algernon has no "ready money," as we learned in Act I.

Because Lady Bracknell has refused her consent to allow Gwendolen to marry Jack, Jack says that he will only allow Cecily, who is his legal ward, to marry Algernon if Gwendolen can be allowed to marry him. Miss Prism is the governess who accidentally put baby Jack into the handbag and left it in the cloakroom at Victoria Station. In terms of the importance of being "Earnest," there is a pun: Ernest is an actual first name, of course, and to be earnest is to possess the quality of seriousness or gravity (ironic, certainly, given how trivial everyone is).

Ultimately, it is not at all important to be Ernest—as both couples seem quite happy to marry, even before they learn that Jack's real given name is Ernest—and because failing to be earnest has actually gotten everyone in the play precisely what they wished for.