In mobile ad hoc networks (MANETs), trust is crucial. It helps organizations deal with the risks and challenges that come with relying on the actions of free agents. Complexity limitations in processing, as well as the free mobility of individual nodes, make trust calculations and management particularly difficult in MANETs. This precludes the use of methods developed for use on different networks. A malicious node in a MANET has the potential to do serious harm and compromise data integrity. As a result, the certainty with which an entity transacts with a node is improved by analysis of the node's trust level. Specifically for mobile ad hoc networks (MANETs), we give a comprehensive overview of many trust computing strategies. We focus on summarizing and contrasting these methods. We also examine the impact of trust on security services and the effects of trust propagation, prediction, and aggregation methods, as well as the effect of network dynamics on trust dynamics.