What is Winston's impressions of O'Brien in 1984?

In George Orwell's 1984, Winston Smith initially perceives O'Brien as an ally and a potential source of rebellion against the Party. He admires O'Brien's intelligence and charisma, interpreting his subtle gestures and enigmatic smile as signs of shared dissent. However, Winston's impression shifts dramatically when he realizes that O'Brien is actually loyal to the Party, ultimately betraying Winston's trust and hopes for freedom. This betrayal highlights the profound manipulation and deception inherent in the totalitarian regime.