lol. How do you know?
Seriously, this is a perfectly valid question.
The Koran actually tells believers that they are to lie to unbelievers. Muslims also say that the only way to fully understand the Koran is by reading it in Arabic.
So, how do you know that what you were taught is actually correct? And please don't say because everyone else says it is, you could well be the victim of a conspiracy!
I always think of Arabic writing as being similar to looking at Roman writing and not being able to read. Different than a foreign language, like German or Spanish, because with those toy can still read it, you just can't understand it! With Arabic you can'yt even read it....
Okay, I'm funning you. GT is crap, but it is convenient and it's all I've got!