Cassie's role was expanded for the screenplay. Diana Ossana said about Cassie: "Cassie somewhat exemplifies Ennis’s continual denial of his emotional makeup, and his attempts to have what he believed was a “normal” relationship with a woman. After his and Jack’s final confrontation about Mexico, Ennis realizes that it is Jack he truly loves, and he simply cannot continue in his attempts at a relationship with Cassie, thus her confronting him in the diner about his whereabouts and her frustrations and painful realization that she’s not 'the one.'"