Trust and its implications in international relations in general, and in conditions of longterm conflict and hostility between opposing states, has been the subject of considerable scholarly attention and debate in recent years. This study addresses the issue of trust in shaping U.S.-Iran relations in general, and in affecting a myriad of complex issues and interactions between the two states, including its role in framing direct or multilateral negotiations on the nuclear issue. The paper situates the discussion of trust in the context of international relations theories and examines the divergent views and approaches of both countries towards trust, the extent of their risk taking in “costly signaling”, and both states’ attitudes and behavior while engaging in both “prisoners’ dilemma” and the “assurance game”. It is argued that Iran's approach towards conflict resolution and overcoming the challenge of mistrust is generally driven by its “strategic culture” of being a “security seeker” which favors playing an “assurance game”. The incongruency between the U.S's and Iran's strategic cultures and thus the U.S. tendency towards “prisoners' dilemma” in mistrusting conditions constitutes a foundational obstacle in bilateral and multilateral diplomacy and negotiations between the two countries.The study thus illustrates the complex and significant connection between trust and the U.S. and Iranian strategic cultures, introducing the concept of natural hubris in U.S. foreign policy identity and its ramifications for the dynamics of trust, and finally, what is termed here the effective balance between the two states.

Keywords: U.S.-Iran relations; trust; natural hubris, prisoners’ dilemma; assurance game; strategic culture; ontological security; costly signaling; effective balance; reflexivity