With the growth of sharing economy, P2P resource sharing services are combined with social networks for improving user experience and giving more trustworthiness to users. For trust management, many P2P resource sharing services adopt feedback-based reputation system. Since peers in services have their social relationship in the community, reputation includes not only trust related to services but also subjective social trust which causes bias of reputation. In this paper, we propose the method that objectifies feedback-based trust by removing social trust from rating points. We conduct simulation and verify the proposed method can objectify feedback-based trust preciously with optimized parameters by using lambda square discrepancy measure.