What do you mean (I am actually a little confused), are you saying that Sasuke
will take Madara's speech at face value, or Sasuke is smart enough to seek verification first? Sasuke has a long line of following, more or less, whatever someone tells him. He believed extensively/intensely in Itachi's words, to the point that he abandonned his village to attain power to continue
believing in Itachi's words. Additionally, he went to Orochimaru for the promise of power, when, for all he knew, Orochimaru could have knocked him out and kept him in a test tube until Orochimaru needed to transfer bodies (in fact that would have been the logical thing for Orochimaru to do, but sadly, Orochimaru has never been that logical in his thinking). Sasuke is very smart and has a deft mind while in battle, but he has a hard time seperating truth from fiction while outside of battle (which is somewhat justifiable considering the fact that he has been, more or less, lied to by nearly everyone for the majority of his life).
I hope that Sasuke does go on a Quest for Verification (tm for next Sasuke arc
), otherwise he will be acting like a puppet (yet again), which would be a great disservice to his character.