If you dream about an assassination, you may have gone through a very bad time in your life, or you may be worried about an impending disaster or misfortune.
You may be afraid of making a wrong decision, and making things worse.
If you dream you are an assassin, try to think about the person your were sent to kill. Was it someone you know, what were they doing? It could be that you don’t want that person in your life anymore, or that you wish they would stop some behavior you don’t like?
If you didn’t know the person you were sent to assassinate in your dream, it could be that the person represents an aspect of yourself that you would like to be rid of?