If you are the one to be struck down by an assassin then you will not experience the realization of your goals.
To see someone else who has been killed, with the assassin still there, and blood spattered, shows some very bad luck to the dreamer, as he/she will be brought low by the underhandedness of an enemy.... Encyclopedia of Dreams
Seeing or experiencing an assassination attempt means startling events are in you future, but “luck can be found even in misfortune”—things could be worse. You are assassinating someone: you are spending time and energy on a hopeless situation—you will not succeed. You see blood: you will experience personal and professional losses. Dreaming about being assassinated: you are in great danger—the utmost concentration is called for.... Dreamers Dictionary