Oh, wrong is such a strong polarizing word . I in this case I would rather prefere to state that there are some ambiguities in Dooku's behavior which are leading to contrary interpretations of his actions and (often very pathetic) speeches. Actually I doubt that Dooku trusted Sidious that much. Somebody said here, that Sidious was just a bit paranoid of killing Ventress who was completely loyal to both, which I doubt. She was loyal to Dooku and her loyalty and admiration for him were surely surpassing her loyalty to Sidious thus being a threat to Sidious. Sidious in TCW-season 3 "Nightsisters" says clearly that he feels a disturbance in the force about Ventress. http://starwars.wikia.com/wiki/Rule_of_Two And please let's examine how Dooku executed the killing of Ventress. He just ordered his commando-droids to bombad the ship on which Ventress was after her ginivex-fighter was made nearly unusable by Anakin. What seems to be a mere compliance to his master's order to kill Ventress is in fact a try to save her life because Dooku deems her capable to escape that forlorn star-ship. If he really wanted to kill her, he would let her end the fight and if she would have come back to Serenno afterwards he would have choked her to death like he did with his other apprentice, Komari Vosa, after Jango Fett brought her to him. But he just couldn't do that - not with his favorite assassine Asajj Ventress. And after Obi-Wan Kenobi and Ventress there was another try of Dooku to topple Sidious, if you watch closely: It was in TCW-season 6 "The lost one" when the Jedi tracked that signal of the space-ship of Sifo-Dyas at that moon of Oba Diah, where the Pykes killed him at the orders of Tyranus. Unfortunately Yoda went directly to the current Supreme Chancellor to ask him about the details of that long-ago mission after Jocasta Nu told him that the chancellor's office is keeping that matter secret. Of course after Yoda's visit in his office, Sidious is interrogating Dooku. He is asking his old apprentice very bluntly in a quite suing manner how it could happen that the Jedi came to know about that crashed ship and it's signal. A question everybody should ask at this time. And then that scene when Sidious orders him to finish this loose end. Now we see again Dooku hesitating and pretending that this would be an issue hard to solve. Of course he finally complies. Then we have that intraplanetary force-choke of Sidious on Dooku. And I suppose Sidious to be fully aware of Dooku's newest plot against him. This force-choke is not just a whim out of sadism or allure. It is instead the punishment of an illoyal apprentice. This time Dooku didn't want to get involved personally but he expected wanted the Jedi to be clever enough to use this volatile information to discover the truth about not only the creation of the clone-army but also about who is behind all that, even when it reveals Dooku's own guilt having been responsible for the killing of Sifo Dyas. That was Dooku's offered sacrifice. But Dooku overestimated the Jedi's intelligence. Actually it was not Dooku who did trust Sidious to much. It were in fact the Jedi who were trusting Palpatine to much.