I have seen "evidence" that we know with a great degree of certainty and accuracy what the original bible said. This is to say, we know what the original authors wrote. I'm not sure how accurate these claims are as they seem to come from biased sources. Here are a few:

https://www.youtube.com/watch?v=cWxwfFNyVws

https://carm.org/new-testament-corrupted

> The short answer is no [the bible was not corrupted]. To answer this question in more detail, let me
> give you some background.  The New Testament is an ancient book.
> During ancient times, there were no Xerox copy machines, and the way
> the Bible was preserved was through hand by hand copying. As a result
> of this copying process, errors would occur by accident or intention.
> However, these errors in the text do not affect any major Christian
> doctrine such as the Trinity, Deity of Christ, salvation by faith
> alone, etc.  Unfortunately, we do not have any original copies of any
> of the books of the New Testament. In other words, we do not have “the
> original manuscript copy” of Paul’s Epistle to the Romans or an
> original copy of the Gospel of Matthew, etc.

http://www.essentialbibleblog.com/2013/03/top-10-reasons-bible-is-true.html 

The first five points at least...

To be clear I'm not asking if the events talked about in the bible are true. **I'm asking do we know the words (or decidedly synonym words) used by the original authors?**