This film marks a significant high point in both the acting and directing. Catherine Sloper, portrayed as a dowdy spinster, finds herself trapped in a monotonous existence, frequently belittled by her domineering father, with her life drifting along without excitement. Suitors avoid her because she struggles with social conventions of the time. Then, at a ball, Morris Townsend showers her with attention; could this be genuine affection? Or is he after her inheritance—an inheritance her father intends to withhold if she pursues him further? Based on a novel by Henry James (Washington Square) and adapted into a successful Broadway play by Ruth & Augustus Goetz (who are also responsible for the film's excellent conclusion), The Heiress translates exceptionally well to the screen, largely thanks to the outstanding contributions of everyone involved. Olivia de Havilland is remarkable as Catherine, whose story follows her development from a downtrodden victim into a mature and insightful woman; de Havilland delivers an exceptional performance—her final look alone might qualify her for the title of greatest icy stare ever captured on film. Ralph Richardson is superb in the role of the father, skillfully blending several character traits with impressive effect. William Wyler’s direction is spot-on, which isn't surprising given that de Havilland specifically requested him for the project, likely knowing he was the ideal director to draw out such a powerful and layered performance. Montgomery Clift delivers a more restrained than exceptional portrayal of Townsend; perhaps at times he seemed overly aware of how brilliantly de Havilland and Richardson were performing. However, even his less impressive work surpasses that of some other actors’ best efforts. A significant addition is the score by Aaron Copland, which begins with a lively feel before evolving into a beautiful, poetic threat in the final act. Accounts of friction on set suggest that both Richardson and Clift expressed disapproval of de Havilland's acting; nevertheless, watching the film now reveals how those off-screen tensions elevated her performance to another level, aided by Wyler’s expertise. The Heiress is a captivating, dramatic, and absorbing movie—a must for anyone seeking artistic skill and a memorable ending that exemplifies class. 9/10

Source on TMDB