Formal:
* Verified: This implies a rigorous process of checking for accuracy.
* Validated: Similar to verified, but with a focus on proving the validity of the information or idea.
* Confirmed: This indicates that something has been proven true beyond doubt.
* Substantiated: This suggests evidence has been provided to support the claim.
Informal:
* Proven: This is the most straightforward and common option.
* True: This emphasizes the accuracy of the information.
* Right: This emphasizes the correctness of the decision or action.
* Accurate: This highlights the precision and lack of error in the information.
Other options:
* Justified: This emphasizes that the claim or action was reasonable.
* Legitimate: This indicates that the claim or action is valid and acceptable.
The best word to use depends on the specific context and the desired level of formality.