When email (or any file) is deleted, it doesn't "go" anywhere. The spot it occupied on the hard drive is eventually overwritten. If it's blocked as spam, it will end up in a spam filter (folder of spam), or be deleted immediately. Again, the spot it occupied on the hard drive will be overwritten eventually.
No, it's not floating around out there in cyberspace just waiting to land in someone else's inbox like unwelcome bird droppings!