In Oscar Wilde's The Importance of Being Earnest, the revelation of Jack Worthing's true identity at the close of the play is the climax toward which the whole comic plot has been building. Its significance lies in the way it resolves the tangled complications, delivers Wilde's crowning irony, and satisfies the play's comedic design.
It resolves the central obstacle to the marriages. Throughout the play Jack cannot marry Gwendolen because Lady Bracknell disapproves of a man who was found as a baby in a handbag at Victoria Station and has no known parentage. The revelation that Jack is in fact the long-lost son of Lady Bracknell's own sister, and therefore Algernon's elder brother, removes this obstacle and clears the way for the union.
It vindicates Gwendolen's fixation on the name Ernest. Gwendolen has insisted she can only love a man named Ernest. The revelation discloses that Jack was christened after his father, General Moncrieff, whose first name turns out to be Ernest. Thus Jack has been Ernest all along, and his double life, pretending to be "Ernest" in town, is revealed to be the literal truth.
It produces the play's crowning irony and title pun. Wilde's final joke is that Jack, who invented the name Ernest as a deception, is discovered to have been Ernest by birth. He declares that he has now learned "the vital Importance of Being Earnest," a pun on earnest (sincere) and Ernest (the name). The revelation crystallises the play's satire on triviality, sincerity and social convention.
It untangles the mystery of the handbag. The revelation depends on Miss Prism's confession that, years before, she absent-mindedly placed the baby in a handbag and left it at the railway station. This clears up the mystery of Jack's origins and ties the plot's loose ends into a neat comic knot.
It fulfils the conventions of comedy. By restoring Jack to his family and enabling the multiple marriages of Jack and Gwendolen, Algernon and Cecily, and even Miss Prism and Dr. Chasuble, the revelation brings the traditional happy ending of comedy, reconciliation, identity restored and unions blessed.
In conclusion, the revelation of Jack's true identity is significant because it removes the barrier to the lovers' marriages, confirms that he really is Ernest, delivers Wilde's central pun and satiric point, resolves the handbag mystery, and secures the comic resolution of the play.