This essay examines the role of sincerity in several recent US Supreme Court cases on religious freedom in which plaintiffs successfully sought religious exemptions from otherwise applicable state or federal laws: Hosanna-Tabor, Hobby Lobby, and Holt. Under a religious sincerity test, law cannot and does not distinguish religion from nonreligion; individual believers can and do. Instead, courts trust a person’s or group’s self-reporting—that they sincerely believe what they say they believe—and adjudicate from that point forward. As a criterion, sincerity invokes a host of epistemological and moral assumptions about personhood, the nature of belief, the substance of religion as somehow equating to belief (a highly contestable assertion), and what it is reasonable for a sincerely religious person to believe and do. Drawing on the work of Michel Foucault, Leerom Medovoi, and José Esteban Muñoz, this essay suggests that sincerity also encodes racialized scripts of proper and improper affect and aligns them with dominant Christianity.