In Nathaniel Hawthorne's "The Marble Faun," the quote "A forced smile is uglier than a frown" highlights the theme of authenticity versus pretense. It suggests that when emotions are not genuine, the facade people put on can be more off-putting than displaying true feelings, even if they are negative. This reflects the struggle many face in social situations where they feel pressured to present a cheerful demeanor, which can lead to insincerity.

This idea resonates with the larger narrative of the book, as characters grapple with their identities and societal expectations. Hawthorne explores the complexities of human emotions, illustrating that true beauty lies in honesty, even if it involves vulnerability. The contrast between a natural expression and a forced one serves as a poignant reminder of the importance of being true to oneself in a world that often values appearances over authenticity.