Your question is exactly the reason why meeting of the minds doesn't solve this problem. It's subjective. Fyi in practice, signing the document means that you

Your question is exactly the reason why meeting of the minds doesn't solve this problem. It's subjective. Fyi in practice, signing the document means that you understand it, as far as a court is concerned. Contracts will often throw in boiler plate like "I am authorized to sign this, I've read it, and I understand and agree to it." The most common way it's successfully challenged is "incompetence" - by showing the person who signed it in no way could have possibly understood it (e.g. developmentally disabled, someone held a gun to their head, don't speak the language and the translation was fraudulent, etc).