Provoke puts you ONE ENMITY ahead of the current player being attacked. So if you use it and the other player is using an attack, spell or whatever he will get hate right back. It's meant to give you the edge in case you die (and start over at zero enmity), or a mob breaks out and you need to make it come back. To maintain hate you need to use Shield Lob, Flash or whatever right after Provoke or it's useless.

Enough testing has been done and it is confirmed. You can think what you want but that's how Provoke works.