Ambiguity is at the heart of the commercial relationship and it bears potentially negative consequences for the image of sales and salespeople. I examine the social representation of the opportunistic nature of commercial activity, the confrontation of norms from the perspective of generalized unilateralism, and conditions for moving to a bilateral relationship. Subjectivity and objectivity in assessing the opportunism of others, and reflexivity in assessing one's own opportunism. Relational, social, legal, and economic processes are designed to limit opportunism by establishing a “law of parties” and allowing third parties to intervene in the transaction. Trust-building is examined jointly with the time perspective of the commercial relationship.