Communicating systems are today composed of a huge number of distributed processes interoperate with diverse kinds of applications, services and actors. It therefore becomes crucial to monitor and manage these trustworthy interactions. For that purpose, passive testing techniques have been used particularly for checking the system conformance w.r.t. its standard. Among these studies, trust behaviors have been monitored in such systems. However, while several approaches have been designed, most of them monitor trust properties that have been manually designed or provided by common database. In this paper, we propose a novel approach to automatically generate trust properties from the study and analysis of the system through process mining techniques and by comparing with the formal specification of the system under test