Well, figuring out the exact twist depends on which specific 'alpha king' story you're talking about, because there are a bunch of them floating around in paranormal romance and dark fantasy. If we're assuming the popular one that's been all over TikTok and Kindle Unlimited lately, the big turn usually isn't about him mistakenly rejecting his mate. That's the setup, not the twist. The real gut-punch comes later when you realize his 'mistake' was a calculated move, not an accident.
He pushes his true mate away to protect her from a bigger threat within his own court, something he can't openly fight without causing a war. So he makes her hate him, makes everyone believe he's cruel and unfit, all while secretly dismantling the conspiracy from the shadows. The twist for the reader is discovering that every act of cruelty, every cold dismissal, was a piece of a long game. The emotional payoff isn't in the apology, but in the slow, painful reveal of the depth of his sacrifice and the loneliness of his position.
It reframes the entire first half of the book. Scenes you read as him being a jerk get revisited in your mind with new context. That's where these stories either shine or fall flat—if the author can make that reframing feel earned and not just a cheap excuse for bad behavior. The better ones weave in subtle hints, like a lingering glance he thinks no one sees, or an order that seems harsh but ultimately keeps her out of a specific danger.