Wireless sensor networks are vulnerable to several attacks, one of them being the black hole attack. A black hole is a malicious node that attracts all the traffic in the network by advertising that it has the shortest path in the network. Once it receives the packet from other nodes, it drops all the packets causing loss of critical information. In this paper we propose a reliability analysis mechanism. The proposed reliability analysis scheme overcomes the shortcomings of existing cooperative black hole attack using AODV routing protocol. As soon as there is a path available for routing, its reliability is checked using the proposed scheme. The proposed reliability analysis scheme helps in achieving maximum reliability by minimizing the complexity of the system. The final path available after the reliability analysis using the proposed scheme will make the path secure enough to minimize the packet loss, end-to-end delay and the energy utilization of the network as well as maximize the network lifetime in return.