Capitu is Bentinho's childhood neighbor, daughter of Pádua, a clerk in an office of the Ministry of War, and of Dona Fortunata. She is fourteen when the book begins, one year younger than Bentinho, and it is because of her that José Dias makes the denunciation that starts the story.
In the early parts of the book, she is the more decisive of the two. She writes with a nail on the backyard wall the two names side by side, and tries to erase them when she is seen. She devises the plan to use José Dias to free Bentinho from the seminary. She corrects the oath at the well so that it obliges them to marry, and not merely to wait. And she explains to Bentinho that she shows herself cheerful before Dona Glória and Cousin Justina so as not to confirm José Dias's denunciation.
She marries Bentinho in March 1865 and has Ezequiel. Around her revolves the book's question: whether she betrayed her husband with Escobar. But Capitu never speaks for herself in a single line that does not pass through Bentinho. Everything known about her is told by him, decades later, already as her accuser. When she is accused, she asks him to tell everything so that she may defend herself; the couple separates, and she dies in Switzerland.