What is the significance of Cunegonde's loss of beauty in Candide?
Depicting her like the heroine of the picareque novel, a heroine who is the idolized beauty of the hero of that genre, Voltaire employs Cunegonde as a symbol of Candide's idealization and innocence. But, while Candide perceives her as this ideal, she is a tool of Voltaire's satire as Cunegonde has all too many human shortcomings.
Cunegonde represents the thematic view of Optimism in which Candide has been educated, an optimistic view of life held by Pangloss that is used to explain all experience. Indeed, this optimism is satirized through the character of Cunegonde. As Candide's inspiration and ideal, Cunegonde spurs Candide, even in his darkest moments, to pursue his dream of being reunited with his love. Candide is so deluded by his perception of Cunegonde as perfection that when he is in Eldorado, where everything is absolutely wonderful, Candide is not happy. Speaking to Cacambo, Candide says,
Once again, my friend, I admit that there's no comparison between this country and the castle where I was born; but it's still true that the castle where I was born; but it's still true that Lady Cunegonde isn't here, and you must have some mistress in Europe, too. If we stay here, we'll only be like everyone else. But, if we go back...we'll be richer than all the kings...and we can easily rescue Lady Cunegonde.
When Candide does rescue her, however, Cunegonde is ugly, bloodshot, and wrinkled. Honorably, however, Candide marries her only to be subjected to a bitter, shrewish woman. Thus, Candide's disillusionment with the world of Optimism is, indeed, reflected in his disappointment with Cunegonde.