that's what somebody thinks

that's what (someone) thinks

Someone is totally wrong about what they think. A: "Bob said he's planning on taking his vacation next week." B: "That's what he thinks—we need everyone here to get this project finished before the deadline!" A: "I need you to stay home this Saturday to look after your sister." B: "That's what you think! I already bought tickets to the concert on Saturday."
See also: think, what
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

that’s what somebody thinks

(informal) what somebody thinks will happen will not happen, especially because the speaker is going to do something to prevent it: ‘Your team doesn’t have a chance of winning.’ ‘That’s what you think!’
See also: somebody, think, what
Farlex Partner Idioms Dictionary © Farlex 2017
See also: