Isabel is the central concern of the novel. She possesses all the attributes of James' typical American. She is innocent, but also intelligent. In contrast to the European such as Madame Merle, she does not possess a great amount of experience, but she does have the capacity to appreciate any new experience.
Isabel has an expansive personality. Ralph Touchett and others are attracted to Isabel because she apparently has a great capacity for growth. This quality allows her to react spontaneously to any new experience. Her response indicates a depth of perception missing from other people. It is a compliment to Isabel's combination of these qualities that she is able to attract so many divergent types of personalities to her. She excites the admiration of people as different as Madame Merle and Henrietta Stackpole, or as different as Gilbert Osmond and Ralph Touchett. Furthermore, men as divergent in personalities as Caspar Goodwood and Lord Warburton both fall in love with Isabel. Therefore, part of her greatness lies in her ability to attract all sorts of people to her.
Even though Isabel is not considered a great beauty, she is attractive enough to win attention. She possesses a natural charm and a sincerity that add to her looks.
Perhaps her most striking qualities are her desire for independence and her imagination. She believes strongly in her own opinion and cherishes the right to evaluate independently any person or situation.
This note of independence is struck in the first chapters of the novel. It is the trait which Ralph admires greatly. In conjunction with her independence, Isabel is also a very imaginative person. Ralph Touchett thinks that in order for Isabel to realize her imagination, she must be made financially independent. Thus, her inheritance gives her the freedom to allow her imagination to soar.
One of the first uses of her free imagination is in evaluating Gilbert Osmond. He told her that he had lived a dull life, but Isabel's imagination took flight to create for him a very interesting life. In her imagination, she filled in the vacant spots and saw him as a much more interesting person than he actually was.
It is ironic that Isabel's desire for complete independence causes her to marry Osmond. In her determination to follow only her own evaluation, she refused to listen to her many friends who cautioned her against such a marriage. Consequently, her highest quality also became her downfall.
Isabel also possesses a rather over-strong sense of pride. Even after she recognizes that she made a mistake in her marriage, she cannot admit this publicly. It took a great effort to confess her error to Ralph, and at the end of the novel, she has too much pride to confess her mistake to the whole world. Thus, partly for this reason, she returns to Rome to continue her life with Osmond.
Isabel, therefore, represents the innocent young American who is deceived by the superior cunning and deceit of Osmond and Madame Merle, who are representatives of the old order of European thinking. Isabel was capable of great potential and of great development — she had a large capacity for growth and for life. Her tragedy is in her mistaken judgment of Madame Merle and Gilbert Osmond. Once, however, she has recognized her error, she is determined to try to make the best of it.