[en] Both argumentation and trust concern multi-lateral uncertainties, while argumentation owns the ability to enhance trust in many ways. In the field of trust service where the trustee administers financial assets on behalf of principals, trust is an indispensable element. Often, the trustees withhold the investment plans and of which the decision-making process from their principals such that these services lack of transparency, documentation, traceability, and inclusive decision-making mechanisms. In this paper, we integrate formal argumentation within a blockchain framework. Both argumentation and blockchain have distinctive features that complement each other. They together make the decision-making of the trustees transparent and traceable in order to gain trust and confidence in principals. We introduce three possible architectures and we evaluate and compare them considering different technical, financial, and legal aspects. Specifically, we discuss the role of argumentation in building trust between trustees and their principals.