Hey Kenny 
Rejecting a post does not notify the user that it was rejected.
When a user submits a post with a watched word and you have it set so that the posts are funneled to the review queue, the user will see a pop-up message that their post is being held for review. They will be aware that it hasn’t immediately been posted.
Discourse keeps a record of everything that has gone through the review queue. You can adjust the filters on the sidebar to get a list of posts that were rejected. For example, if you set the filters to the following, you will see all rejected posts that entered the queue at some point, sorted by most recent.
