Mami (Altagracia Batista) is Xiomara and Twin’s mother and the novel’s primary antagonist. Mami is a devoutly religious Catholic who tries to control her family, especially Xiomara, to mitigate her own life’s disappointments. Mami’s frustration and bitterness stem from the fact that her dream of being a nun was stolen from her when she was unwillingly bartered in an arranged marriage to Papi, a man reputed to be a womanizer, so that her family could gain access to the United States from the Dominican Republic. As a result, Mami has a low opinion of men and relationships, and she projects her issues onto her daughter.  

Though Mami and Xiomara had a kinder relationship when Xiomara was a child, Mami sees Xiomara’s maturity and growing independence as a sign she is losing control over her. Mami’s need for and lack of control is reflected in her need to dominate Xiomara’s body, mind, and soul. Mami demands that Xiomara focus on church and, to a lesser extent, school. When Mami sees Xiomara kissing Aman on the train, she interprets what she sees as a sure sign that Xiomara has strayed from the correct path. She is furious, and she abuses Xiomara by forcing her to kneel on hard rice in front of an image of the Virgin Mary. She beats Xiomara and calls her a cuero, the Dominican word for whore.  

When Mami finds and reads Xiomara’s poetry, her fears about her daughter are confirmed. She interprets Xiomara’s normal sexual desires, her questions about the faith she feels forced into, and her resentment toward Mami as rejections and as signs that Xiomara is hell-bound. When Mami burns Xiomara’s poetry journal, she hisses at Twin and Papi as they try to defuse the situation, ironically bringing the story’s Edenic allegory full circle.  

Despite their shattered relationship, after Xiomara seeks help from Father Sean, Mami shows signs of trying to accept her daughter for who she is. Mami goes to Xiomara’s poetry reading to support her, and afterward she invites Xiomara’s friends to celebrate, including Aman.