The Mobile Ad hoc Network (MANET) is the collection of some mobile devices that communicate with one another without any help from a centralized administration. For this, the energy is an important issue that has to be addressed since the ad-hoc network nodes have a limited battery power. A secure routing in the MANETs is an area of research that is emerging. The designing of a security protocol which is trustworthy for the ad hoc routing is an extremely challenging task owing to all its unique traits. Due to its minimal configuration and its quick deployment, the MANETs are found to be well-suited for situations in the case of an emergency such as the natural disasters or the military applications. This way, a transfer of data among two nodes need some security. A MANET black-hole attack will occur owing to the malicious nodes attracting data packets by means of a false advertisement of a fresh route to its destination. For this work, the trust-based routing along with the packet forwarding probability. For this work, the Ad hoc On-Demand Multipath Distance Vector Routing (AOMDV) protocol is used and for finding the routing path a trust value will be piggybacked with a route request packet. There was yet another novel algorithm for optimization known as the Group Search Optimizer (GSO) algorithm that was proposed inspired by the behaviour of animals. This GSO-AOMDV was for the purpose of improving the performance of the network. The results of the experiment proved that this method proposed could achieve a better performance compared to the other method.