In what way does Saina misinterpret her relationship with Billy in the novel, The Wangs Vs The World?

Billy's articles about Saina's early career helped to launch her into super-stardom in the art world. Saina and her friends were older than him, but when he arrives at her Helios, New York farmhouse to do an unscheduled interview with her, Saina realizes that their relationship has changed. She realizes that what she saw as friendship between the two of them was always only a professional relationship based on what each could get from the other.

Billy writes the article despite Saina's wishes for privacy and without her help. By the time the article is published, however, Saina's family has arrived and his words no longer have the power to destroy her that they once might have had.