How Do I Relieve My Girlfriend That I Am Dead?

How do you reassure your family about the possibility of death when you worked your old job? I'm starting a career as a law enforcement officer and my girl friend is terrified that one day someone will knock on our door and tell her, i am dead. What can i say to her in order to ease these thoughts? I have promised her it will be ok, but obviously i can't be sure. Any advice would be greatly appreciated.