Lord Warburton still loves Isabel, and Isabel is just as obviously taken with Gilbert Osmond. It hurts Warburton to see them together; one night at the opera, he hurries away after seeing them seated next to one another. On his way out, he sees Ralph, who also seems miserable. The next day, Warburton tells Isabel that he is leaving Rome, because he is unable to stand being near Isabel in these circumstances. Isabel does not know whether to turn him away coldly or to treat him with kindness. She tells Osmond that she likes Lord Warburton but has no real interest in him. Osmond, who longs to be an aristocrat, thinks smugly to himself that it will be a feather in his cap to win a woman who turned down an English nobleman.
During his time in Rome, Osmond is so charming that almost everyone in Isabel's life is taken in by him. Osmond is thrilled with his success; he likes everything about Isabel, except that she is too eager to praise things and to enjoy things in which he sees flaws. Isabel prepares to leave on a trip to Bellaggio with Mrs. Touchett and wonders to herself whether she will ever see Gilbert Osmond again. Before she leaves, Osmond tells her that he loves her. Isabel is overcome with emotion, but she is also confused, and she asks him not to say such things to her; she says that she does not know him. Osmond says that he does not want anything from her, as he has nothing to offer her; he merely wants to enjoy the feeling of being in love with her. He tells her that he is glad she is going on the trip with her aunt, as it is the perfectly conventional thing to do. And he asks her to look in on Pansy on her way.
Alone, Isabel ponders this new development. She has been fantasizing about being in love with Osmond, but now that he has confessed his love, she feels strangely oppressed. She feels as though there is a space inside her that she is unable to cross, but that if she could cross it, she could return Gilbert's love.
Ralph escorts Isabel back to Florence, where she pays the promised visit to Pansy. She finds the pretty girl practicing the piano. She is amazed at how natural and simple Pansy seems, despite the extraordinary regimen of her education and upbringing. Pansy seems to live to please her father; she repeats to Isabel all the instructions he has given her about how to spend her time, and Isabel agrees that Pansy must do all she can to please him and obey him. Pansy concurs, noting that her father is inwardly a sad man. Isabel longs to ask Pansy what she means, but Isabel feels that it would be unfair of her. When Isabel kisses Pansy good-bye, she feels a strange pang of envy about the girl; she longs again to ask Pansy for insight into Osmond's character.
A year passes, during which Isabel spends five months vacationing with Lily, her sister, and Lily's family, and she chooses not to tell her sister about all the romantic developments in her life, such as Warburton's proposal. She thinks of Osmond almost constantly but feels that to tell Lily about him would drain the romance from her situation. Lily, for her part, finds Isabel vaguely disappointing; she had expected that Isabel would be a popular socialite, but instead she seems to be her same old introverted self. When Lily leaves to return to America, Isabel feels a powerful sense of relief. She hurries back to Rome to take a trip through the east with Madame Merle. Watching events from afar, Mrs. Touchett is pleased that Isabel has not returned to Florence to be with Gilbert Osmond.
After a three-month journey—Isabel pays Madame Merle's way across Greece and Turkey—Isabel feels as though she has learned a great deal about Madame Merle. She was married to a Frenchman who treated her cruelly, and Isabel notices a slight cruel streak in Madame Merle as well; she sometimes even finds her ominous or depressing. But she admires Merle for retaining her interest in life despite her unpleasant experience with her husband.