Moving beyond conventional understandings of trust as an individual attitude or institutional outcome, Trust Cultures and the Politics of Relational Legitimacy develop the concept of trust cultures to explain how historically and culturally situated publics learn to navigate uncertainty, recalibrate expectations, and sustain democratic life despite persistent institutional fragility.Trust is understood not simply as confidence in institutions but as part of a broader relational process through which legitimacy is continually negotiated, contested, repaired, and reconstituted. Drawing on interpretive analyses of public health controversies, local governance, political scandals, and everyday democratic life in the Philippines, the book develops an interconnected conceptual vocabulary—including relational legitimacy, democratic ambivalence, scandal constructivation, accrued damage, fragile repair, and moral coordination—to demonstrate that democratic endurance depends less on institutional perfection than on the relational capacities through which citizens continue inhabiting imperfect institutions. Rather than treating the Global South as a site for applying theories developed elsewhere, this book advances it as a site of theory generation. It argues that postcolonial democracies illuminate broader dynamics of legitimacy, uncertainty, and democratic endurance that increasingly characterize political life across the contemporary world. Bringing communication research into conversation with cultural sociology, political sociology, democratic theory, and interpretive social science, this book offers a relational account of democracy in which trust is understood not as the absence of uncertainty but as one of the relational infrastructures through which democratic societies learn to live together despite it.This work is essential for scholars, researchers, and practitioners in political communication, sociology of emotions, trust studies, and Southeast Asian/Global South studies. It speaks to those grappling with the challenges of disinformation, affective polarisation, and the erosion of institutional legitimacy in fractured democracies, offering a Global South-rooted perspective that redefines trust as a relational, emotional, and ethical dynamic.