You will find a lot of information on this subject in the forums on the net. Black magic has the problem that there are often some complications after it. 

And black magic is not stronger than white magic?

@zabojad yes but it is dangerous

Black magic doesn't have to be dangerous at all, but that's provided that. ritual is properly executed.

Black magic, that is, for example, love entanglement should be used when there is no chance for the effects of white magic. Otherwise it is pointless.

I have tried a couple of people and there are no results. Who do you recommend?

@zabojad Julia Koppel and Daria Kwiatkowska, are said to be one and the same person. Note to them.

@seekinghelp There are also complications after white magic. An example? A friend of mine once confided in me that every time he tries to do something it doesn't work out, he gets discouraged, he is unable to do anything. It's as if he is standing still. The reason is excessive visualization , tarot stacking and generally messing with his energy by a girl in love with him. Ever since she has been unattached his problems and impotence have disappeared.