This paper describes a trusted lightweight synchronisation protocol for wireless ad-hoc networks. The wireless ad-hoc network and wireless sensor networks is a large field of research. Their dynamic topologies make them difficult to synchronise (power consumption, slow convergence, accuracy). Moreover, these open networks are vulnerable to faulty nodes and attacks from malicious nodes. In this paper we propose to use the Simple Synchronisation Protocol (SiSP) enhanced with trust aspects making it more robust to attacks. We describe how to observe deviant behaviour and assign a confidence level to each node. Countermeasures are then adapted to the neighbourhood confidence level. The last part present simulation and results on the MASH simulator.