The next night, Henry and Basil get to the restaurant before Dorian, and they take advantage of the opportunity to discuss Dorian's sudden engagement. Basil doesn't approve, but Henry looks at it lightly as a part of his experiment. He hopes that marriage won't ruin Dorian, and that the boy will marry Sibyl, love her madly for a little while, and move on.
Dorian shows up in the middle of this heated discussion. He's in a jolly mood, and he recounts the story of his engagement to Sibyl.
The night before, Dorian watched Sibyl perform in As You Like It, and was overwhelmed by his adoration for her. Backstage after the show, they kissed and exchanged vows of love.
Back to the present—Basil is slowly won over by this story, convinced that Dorian really is in love with the girl. Henry is still incredulous and, as usual, expresses his cynical viewpoint.
Dorian laughs Henry off, saying that being with Sibyl undoes everything Henry's done to him—she makes him forget all of Henry's "poisonous" theories about life and love.
Henry goes off on another of his philosophical binges, this time about goodness, morality, and women. He basically thinks that everyone should just be concerned with themselves and their own pleasures. Basil and Dorian disagree, but Henry persists in putting forth his ideas. Oh yeah, and he also thinks that women are pretty worthless—in his estimation, they're always hanging on to men, preventing them from attaining greatness.
Dorian promises that Henry will feel different about all of this once he's seen Sibyl Vane. Henry demurs, admitting that it's possible that he'll be really taken with her. They leave in Henry's carriage, and poor Basil has to follow in a cab.
During his solitary ride, Basil is saddened by the feeling that Dorian is lost to him forever—the marriage will drive them apart. However, he reasons, it's better than some things that could have happened to his young friend…