Synonyms for True:
General:
* Accurate
* Authentic
* Correct
* Genuine
* Legitimate
* Real
* Valid
* Veritable
* Actual
* Precise
* Exact
* Faithful
* Right
More specific:
* For statements: truthful, factual, honest, reliable, credible
* For objects: genuine, authentic, original, unadulterated
* For emotions: sincere, heartfelt, genuine
* For relationships: loyal, faithful, devoted
Antonyms for True:
General:
* False
* Wrong
* Incorrect
* Untrue
* Fake
* Artificial
* Counterfeit
* Phony
* Spurious
* Fictitious
* Unreal
* Inaccurate
* Mistaken
* Delusional
More specific:
* For statements: false, fabricated, misleading, deceptive, dishonest, untrue, fabricated
* For objects: fake, imitation, counterfeit, forged, spurious, artificial
* For emotions: insincere, superficial, hollow, feigned
* For relationships: disloyal, unfaithful, fickle, treacherous
The best synonym or antonym to use will depend on the specific context of the sentence.