When Cecily and Gwendolen first meet at the Manor House, Cecily introduces herself as "Mr. Worthing’s ward."
At first, their conversation is polite and friendly, with Gwendolen believing that Cecily is simply Jack’s responsibility. However, tension arises when Cecily casually mentions that she is engaged to "Ernest Worthing."
This shocks and upsets Gwendolen, as she believes that she is engaged to "Ernest" (who is actually Jack). This leads to a hilariously passive-aggressive tea scene, where the two women politely insult each other over tea and cake, each believing the other is trying to steal her fiancé.
Would you like a breakdown of that tea scene and its deeper meaning in the play?