Wireless sensor networks (WSNs) are increasingly being used in a variety of applications, such as smart healthcare systems and the Internet of Things (IoT). Trust in WSNs is the confidence in secure, efficient collaboration among nodes, crucial for reliable data packet routing. However, their susceptibility to trust-related challenges such as different threats, high energy use, and communication issues among nodes, pose substantial challenges to data integrity and availability. Recognizing the pivotal role of trust in ensuring secure data exchange and dependable device communication within the IoT framework, this paper introduces a novel trust-aware optimization technique. The approach integrates trust management into routing protocols, employing the resilient decision-making algorithm Dempster-Shafer Theory (DST) for trusted clustering and the Whale Optimization Algorithm (WOA) for routing. The primary objective is to enhance the reliability and energy efficiency of WSNs by incorporating trustworthiness considerations into optimal cluster and route selection. The proposed DST-WOA technique is evaluated using the MATLAB Simulator, demonstrating a significant 23%, 22%, and 4% improvement over existing protocols (TBSIOP, SQEER, SSDBN-TAA) in network lifetime, energy efficiency and throughput, respectively. The proposed research contributes to the development of more robust and sustainable WSNs for applications in areas such as smart healthcare systems, and IoT.