This article aims to interrogate ourselves about the nature of relationship between governments and nongovernmental organizations including financial relationships. If economic theories can be a support to analyze these relationships in a particular perspective of asymmetry, they do not, however, highlight the interdependance between the different actors which are mostly based on relationships of trust. Then, we want to know how theses links are built. We rely on the work of Sako (1992) for the highlights because they explain that contractual relationships are embedded in social relations through three types of trust : contractual trust, competence trust and goodwill trust. Using a qualitative methodology, we illustrate the relationship between four NGOs (Médecins Sans Frontières, Médecins du Monde, Action Contre la Faim and Care France) and three governmental or intergovernmental actors (French Ministry of Foreign Affairs, European Community Humanitarian Office (ECHO) and United Nations High Commissioner Refugees (UNHCR). The main results show us, through a description of the expectations of the actors, that the asymmetric information are numerous and interdependencies between actors are fundamental to building a long-term relationship. It is built in active communication, and professionalism demonstrated in the willingness of actors to act beyond mere contractual relationship previously built.