Countermeasures for node misbehavior and selfishness are mandatory requirements in Mobile Ad hoc NETwork (MANET). Selfishness nodes cause lacking in transmission which cannot be solved by classical security mechanisms as this method concentrate only in the correctness and integrity of an operation. In this paper, the authors suggest a new routing protocol Trusted Path Routing Protocol (TPRP) to enforce cooperation among the nodes of the MANET and to prevent selfish behavior. Each mobile node in the network maintains a data structure called Trust and Reputation Table (TRT) to keep track of other node's behavior. Deciding a node to be malicious involves decision making and hence it is a problem of uncertainty.