Marriage is the central concern of Oscar Wilde's The Importance of Being Earnest. It supplies the plot, motivates almost every character, and gives Wilde his target for satirising Victorian attitudes to love, class and money.
Marriage drives the plot. The action springs from two courtships: Jack Worthing's desire to marry Gwendolen Fairfax and Algernon Moncrieff's pursuit of Cecily Cardew. Every complication, the double identities as "Ernest," the deceptions, the confrontations, arises from the characters' efforts to marry the partners they want. The play ends, as comedy demands, in the promise of three marriages.
Marriage as a social and financial transaction. Through Lady Bracknell, Wilde exposes the Victorian view of marriage as a business arrangement rather than a union of hearts. Her interrogation of Jack concerns his income, property, politics and pedigree, not his affection for her daughter. She approves of Cecily only after learning of her large fortune, revealing marriage as a market governed by wealth and social standing.
The idealised name over the man. Gwendolen and Cecily both insist that they can only love a man called Ernest, valuing an ideal image and a name above the real character of a suitor. Wilde mocks the romantic illusions and superficial standards that Victorian young women were taught to bring to marriage.
Contrasting views of matrimony. Algernon's cynical epigrams ("in married life three is company") and Lady Bracknell's mercenary calculations sit beside the young lovers' romantic enthusiasm, so that the play surveys marriage from several angles, all treated comically.
Conclusion. Marriage is thus supremely important in the play, both as the engine of the plot and as the theme through which Wilde satirises the snobbery, hypocrisy and mercenary calculation of Victorian society. It is the subject on which nearly every joke and every twist depends.