Based on WeChat, the most popular social media application in contemporary China, this ethnographical case study reveals that the development of parental trust for teachers presents as an incremental process. It derives from parents' access to information shared by teachers online, unfolds across their engaging in constant collaborations with teachers, and increases with the formation of their close affective ties with teachers. Such a process is greatly dependent upon the formation of parents' "liangxin" (which is typically translated in English as "conscience") in regard to teachers. This study, conducted before the COVID-19 pandemic began, indicates that social media like WeChat has turned out to be a critical agent in parents' relationship with teachers that intervenes in their meaning-making process as well as their experience of building trust towards teachers.