Whole-hearted is a term that is used to describe someone who is sincere, genuine, and enthusiastic about something. It is a positive attribute that is valued in both personal and professional settings. However, there are various synonyms that can be used to express this same sentiment. For instance, you can use words like authentic, earnest, fervent, passionate, or dedicated to describe someone who is whole-hearted. These synonyms can be used interchangeably depending on the context of the situation, and they all point to an individual or group of individuals who are committed to a particular cause or purpose with complete resolve.