Here's why:
* Subject-verb agreement: The subject of the sentence is "you," which is singular. The verb should agree with the subject and be "are," not "are."
* Word order: The sentence is missing a verb. It should be "You are not exaggerating this."
* Meaning: The sentence is also unclear. It might be trying to say "You are not exaggerating about this."
Here are a few ways to correct the sentence:
* "You are not exaggerating."
* "You are not exaggerating about this."
* "This is not an exaggeration."