A number of V2X (Vehicle-to-Everything) messages are standardized by the European Telecommunication Standardization Institute (ETSI), such as CAM (Cooperative Awareness Message) and CPM (Collective Perception Message). Since road safety and traffic efficiency are on the basis of the assumption that correct and accurate V2V messages are shared, ensuring the trustworthiness of these V2X messages becomes an essential task in IoV (Internet of Vehicles) security. However, containing sensitive information makes V2X messages susceptible to malicious insider attacks from compromised vehicles after the PKI (Public Key Infrastructure) authentication step, such as Ghost Vehicles (GV) (Gyawali and Qian, 2019), passively or actively reaching a 'ghost' state in terms of communication, position, etc. By integrating CPS (Collective Perception Service) in the Veins simulator, our work aims to propose a trust assessment model in IoV against several types of CAMand CPM-based GV to increase security. The simulation results provide a preliminary analysis of the feasibility of the proposed model and show the effectiveness in terms of assessing V2X messages' trustworthiness.