This article considers the role of trust in teacher professional learning as a form of policy enactment. Drawing upon an experienced teacher's understandings of an assessment policy, "Growing Success," in Ontario, Canada, we foreground the sociality of trust and how trust is an essential ingredient for teacher learning as policy enactment. Using a narrative methodology, we investigate how this teacher engaged in two parallel professional learning opportunities, centered on the same policy. These opportunities fostered very different, conflicting perceptions of the policy. In this way, our work indicates how a single policy may be interpreted as more or less 'disciplinary' or 'developmental,' depending on the relations of trust that are ascribed to it through the professional learning opportunities that attend its enactment. Based on our analysis of the data, we conclude that professional learning contexts need to be 'trust-rich' if they are to serve as a vehicle for meaningful policy enactment.