One day, a member of Inner Party, O'Brien, calls Winston and Julia to give them "The book", a document that contains the truth about Big Brother. They take it and go back to their room to read it. However, they are discovered and arrested by the Thought Police. It turns out that Mr.Charrington is an agent. In the end/Ultimately, O'Brien wants to torture Winston in room 101, and he says that this room contains his biggest/greatest fear in the world. Winston sees the rats above his head which are ready to nibble him, and he yells for them to do it to Julia. O'Brien tortures and brainwashes him until he fully believes in the Party and its doctrines.
After all, Winston is released to live out his final days as a broken man. He encounters Julia, and feels nothing. He says that he was spied on her/betrayed her and she says the same.
In the end, he sees a picture of the Big Brother and cries because he loves him so much.

Again, excellent!