you have to be on the news and have the possibility of having enemies. also, most of the people in your country have to know your name, and it helps if lots of people in other countries do too.
Personally, it's a bit of both. You need enemies to be assasinated, but it also depends on HOW you were killed.
An assassination is "to murder (a usually prominent person) by a sudden and/or secret attack, often for political reasons." Wikipedia this shit.
This^ Assassination is the killing of a public figure. All assassinations are murder. Not all murders are assassinations.
The only reason Chuck Norris is famous these days is because pathetic losers from the internet just won't let the equally pathetic meme he's become go.