Blood Diamonds, how do you know if you are being sold one in reality?

How do you know that there are not any bodies on your diamonds when you purchase a ring with a diamond in it? Sierra Leone and other places in that region that has Blood Diamonds have to be selling them somewhere. It is like the Japanese and their whaling, there is suppose to be a ban in them but they Japanese still whale because there is still money to be made doing it. Even though we are more partial to emeralds to find a sizable emerald that also has few flaws is much harder to find than diamonds in spite of the price, but if there is any diamonds in the engagement and wedding ring how can I really be sure it has no Blood Diamonds in it and there are no bodies on it? They are still mining them and fighting over them and they would not be if there were nor profit in them, so who or where are they selling them and how are they not making there way into the legitimate diamond market?