I’m working on a fanfic right now and I cannot stop thinking about the weight Spike was carrying going into the series finale.
Remember back in Help when Cassie gives him that prophecy? She tells him: “You die, she’s right there, and she’ll tell you.”
In my headcanon, Spike obviously knew he had months to prepare in the back of his mind, but it doesn't truly click until the very end. The moment he realizes what the amulet does the moment he realizes he is the champion who has to stay behindhe has this sudden, terrifying, beautiful epiphany. He thinksI’m going to die, and she’s going to say it.
Because he has those final hours to think about it, his reaction to Buffy's love confession in the Hellmouth is thought-out.
When Buffy says "I love you," she means it with her entire heart. Buffy isn't the type of person to throw those words around lightly just because the world is ending. It wasn't just a heat-of-the-moment confession made out of panic or pity. She genuinely, deeply loved him.
But Spike uses the realization Cassie gave him to build the ultimate emotional defense mechanism for Buffy's sake.
By answering with, "No, you don't. But thanks for saying it," he is actively ensuring she doesn't get trapped by a tragic, ghostly romance. He doesn't want her future tied to a vision of a dead man. Instead, Spike completely absorbs the weight and the tragedy of her love, holds it close to his burning chest, and uses his final breath to free her. He dismisses her words not because he doubts them, but because he loves her enough to let her walk away and just live her life.
I am using all my fandom clout to declare this canon. So mote it be.
