In Vehicular Ad hoc networks (VANETs), spy or malicious vehicles can disrupt communication by dropping, modifying, or redirecting packets. Monitoring and detecting suspicious vehicles is an important task in VANETs. In this context, this work proposes an adaptive promiscuous mode-based watchdog mechanism with route rater (APM-OWMWRR) for secure and reliable route recognition in VANETs. The proposed APM-OWMWRR operates in four stages. The first stage utilizes promiscuous mode to calculate the trust score and a threshold value for the trust score. The second stage implements a watchdog mechanism to monitor vehicles to identify malicious ones. The third stage ranks vehicles according to their trust scores. The fourth stage finds a valid path for data transmission. The final stage calculates the average rank of the identified paths based on the vehicles involved. The proposed method identifies the optimal path, which is free of malicious vehicles for data transmission. The system is simulated in Network Simulator 2 (NS2) and compared with the Weighted Clustering Algorithm (WCA), Enhanced Location-Aided Ant Colony Optimization (ELAACR), and Hybrid Multi-Hop Routing Mechanism with Intelligent Transportation System (HMRW-ITS). Results indicate that the projected APM-OWMWRR outperforms ELAACR and HMRW-ITS in terms of packet delivery rate (PDR), end-to-end delay (EED), throughput, and computational complexity (CC).