In life, trust is considered the base of all relationships, including Business-to-Business (B2B) relationships. The selection of a supplier depends not only on its reputation and the costs involved, but also on its trustworthiness and other factors. But how can the trustworthiness of a supplier be measured? What are the factors that influence the supplier’s trustworthiness, i.e., what are the relevant factors of trust in the selection of a supplier in a B2B relationship? Answers to these questions will help model the supplier agents’ behavior in the multi-agent ANTE platform. In this paper we propose to consider fifteen attributes to measure the trustworthiness of a supplier as a conceptual model of trust, coming out of a combination of several determinants gathered from the literature review. Raw data was gathered by sending a questionnaire to a set of firms from different industrial sectors. The results support part of the proposed determinants, introducing new determinants of trust that resulted from exploratory factor analysis and a new model obtained from confirmatory factor analysis. With this, two possible multi-attribute supplier agents can be modeled. This paper discusses the results and limitations of this study and proposes suggestions for future work.