The disruptive technology of fourth industrial revolution has built new business models. The gaining popularity of social networking sites has facilitated the e-tailers to capitalise the user’s conversations. This gave rise to social commerce- ecommerce through social networking sites.It is significant for marketers to understand the consumer decision making process in the social networking sites. In this framework, the impact of Trust & social commerce constructs - Recommendations & referrals, Forums & communities, Ratings & reviews are studied. Data was collected through structured questionnaire. The study was carried among active social networking site users who purchased fashion products online recently (Less than 6 months). Based on the 581 respondents, regression analysis is carried out to study the impact. The study revealed significant impact of trust and social commerce construct on the consumer decision making. The study provides a guideline for marketers comparing the role of trust & social commerce construct for marketers to strengthen and/or reinforce its usage.