The role of trust in long-distance trade has been a topic of inquiry and debate among economists, sociologists, and historians. Much of this literature hinges on the social, legal, and economic structures that undergird, if not obviate, the concept of trust. This article draws on assemblage theory to suggest that trust in Indian Ocean trade is better understood as a key component of a commercial assemblage. Laws or social mores are not external to but rather enrolled within an assemblage constituted by people, commodities, profits, and “feelings,” as well as judicial systems. This conceptualization of trust is demonstrated through a close analysis of one trading relationship between a Somali merchant and an Indian merchant based in Aden and trading in the Idrisi Emirate of Asir. They established a partnership to exploit elevated prices in Asir during the First World War. After several months of trading, accusations of fraud and embezzling unraveled the partnership and entangled both men in years of legal battles. By tracing the changing socio-material assemblage of this partnership, the article demonstrates how trust should be understood as a dynamic and contingent factor in the operation of commercial agency.