How do theists justify the translations of the scriptures?

[mordant]

The Bible, or any other holy book, is a translation of scriptures written thousands of years ago, and even in different tongues.

How can theists confirm these translations are 100%, or even somewhat, accurate?

One would think that if God wants to deliver such an important message, it would be translation and time proof. But I am sure that the Bible is different even in modern bibles of different languages, and even of the same language.

The problem with written revelation isn't so much translation or even manuscript copying, it is interpretation.

It is a fairly objective exercise for any qualified expert in the source and target languages to tell you if a translation (e.g., from ancient Hebrew or Koine Greek to English) is accurate or not. Translation isn't a 100% objective exercise, so some experts will disagree on some fine points. But if the original says you must not wear mixed fabrics and the translation says you must not engage in jibber-jabber, then the translation is wrong. Not rocket science really.

There is a discipline called "lower criticism" that has been used to demonstrate that even many generations of scribal copies don't usually present any appreciable issue with us feeling we have substantially accurate copies. When there are errors or "pious frauds" they are usually pretty obvious, and the textual evidence is improving all the time. I think the most telling evidence that the manuscripts are "close enough" to not waste time arguing about it is that no great controversy has arisen from the source material for the earlier translations like the KJV (based, usually, on the Textus Receptus) vs more recent 20th century translations (based, generally, on Westcott and Hort's collection and more recent discoveries of older manuscript fragments discovered since). In other words no textual evidence has arisen that anything consequential in the scripture was lost or corrupted and then restored by discovery of older manuscripts, thus creating some kind of theological crisis.

The MUCH bigger problem is in what's called hermeneutics. This is the interpretation system used to decide what scripture means once you obtain a document and translate it. THAT is where the hilarity ensues. That's where everything devolves into debates between Armenians and Calvinists, the countless schools of eschatology, on what to take literally or figuratively and HOW literally or figuratively, what to (de)emphasize and so on. It's largely what gives rise to the countless denominations within Christianity (some denominational differences are just cultural or personal preferences but whether or not for example one can "lose" one's salvation is a matter of hermeneutics).

So I agree with you that written revelation sucks as a vehicle for delivering important information in a clear and unambiguous fashion -- just not for the reasons you raise. The basic problem is that the Christian scriptures, like all holy books, were written in a vague manner to begin with that allows you to take from it more or less what you wish, and gave rise to tea leaf-reading exercises where you now have different "camps" who claim to have the correct hermeneutic (interpretational system) to untangle all the resulting confusion.