What words you can use instead of true?

Here are some words you can use instead of "true" depending on the context:

Formal:

* Accurate

* Correct

* Valid

* Authentic

* Genuine

* Verifiable

* Factual

* Real

* Precise

Informal:

* Right

* Real deal

* The truth

* For sure

* Definitely

* Absolutely

* No doubt

* Honest to goodness

* The real McCoy

Literary:

* Veracious

* Authentic

* Unfeigned

* Unerring

* Unquestionable

* Indisputable

More Specific:

* Exact (emphasizes accuracy)

* Proven (emphasizes evidence)

* Confirmed (emphasizes verification)

* Unassailable (emphasizes certainty)

The best choice will depend on the specific situation and the desired tone.