can’t believe it’s not already
The courts can already do this - perjury is already a criminal offence, and people have been charged and convicted of this. The court case when someone is accused of perjury will explore things like “And what if they interpreted something incorrectly but believed they were telling the truth”. The courts will decide if the evidence shows if someone is lying, just as they do with perjury.
The courts already know the difference between saying something misleading because you were simply wrong (that’s not lying, that’s just being wrong), and saying something misleading with the intent to mislead (lying).