Security and privacy will play a pivotal role in the commercialization of Vehicular Ad-hoc NETworks (VANETs). Traditionally, both cryptographic and non-cryptographic approaches have been used by researchers to address security and privacy issues and achieve secure Intelligent Transportation System (ITS) applications. However, some security goals such as trust and reputation, are still hard to achieve through conventional cryptographic approaches. Trust is the degree of certainty with which the received information is accepted and acted upon. Historically trust has been computed for both the content generator and the content itself with former known as entity trust and the latter known as data trust. Both entity and content trust are equally important to support trustworthy communication in VANET. We review, analyze, and compare some of the recently proposed trust establishment and management mechanisms (from 2014 to 2019) in vehicular networks. Furthermore, we also discuss the weaknesses and inadequacies of existing trust establishment and management approaches when deployed in a VANET environment. Finally, we discuss some future challenges that will need to be addressed for trustworthy communications in vehicular networks.