Why do people trust each other? Do people form groups through mutual trust or self-interest? How does the theory of rational choice and accompanying individualism affect the concept of social capital? Are social cohesiveness in groups and financial success related? Such questions generate interest in conditions promoting association and group emergence, such as trust, reliability, reciprocity, and shared values, which are inherent factors for cohesion. Self-help groups (SHGs) in an urban context are used to comprehend the aforementioned questions. The proposed study is based on the following hypothesis: the formation of groups is not based on trust but on material- and non-material- need-based individual rational choices that force them to cooperate with each other. It is found that a sense of insecurity among migrant women, an emotional need, led the formation of the imagined communities and has paved the way to construct trust. Thus, trust is found to be secondary in construction and sustainability of social capital. Castes, regions, and religions are strong factors; however, they are found to be less effective for the migrants than native SHG members. Therefore, among migrants, trust channelized itself vertically around a sense of fear.