A wireless ad hoc network is a collection of mobile nodes with no fixed infrastructure. The absence of central authorization facility in dynamic and distributed environment requires collaboration among nodes. When a source searches for a route to a destination, an intermediate node can reply with its cached entry. To strengthen correctness of such routing discovery process, we propose a method in which the intermediate node requests its next hop to send a confirmation message to the source. After receiving both route reply and confirmation message, the source determines the validity of path according to its policy. As a result, this strategy discourages malicious nodes from intercepting packets. Simulation results show remarkable improvement in throughput (30% higher delivery ratio and 10% less data transmission overhead) with moderate increase of control messages.