General antonyms:
* Understate: To present something as less important or significant than it really is.
* Minimize: To make something seem less important or serious.
* Downplay: To make something seem less important or significant.
* Tone down: To make something less extreme or intense.
* Dampen: To reduce the intensity or excitement of something.
More specific antonyms:
* Underestimate: To form a lower opinion of something than it deserves.
* Be realistic: To be practical and sensible about something.
* Be objective: To be unbiased and fair in one's assessment.
* Be accurate: To be correct and precise.
* Be truthful: To tell the truth without embellishment.
The best antonym will depend on the specific context of the sentence. For example, if someone is exaggerating a story, you might say they are "understating" it if they are making it seem less exciting. If someone is exaggerating a problem, you might say they are "downplaying" it if they are making it seem less serious.