You can only fully trust the KJV and the NKJV.
No, neither translation can be fully trusted.
The KJV is one of the few translations that teaches there is an "
end of the world," (
Mt. 13:49) and it does so because it mistranslates "
aionos" as "
world." when the Greek should be translated "
age." The link I just provided shows the word is "
aionos," and not "
kosmos,"
AND that link shows the Greek is uniform in all the sampled manuscripts, include Westcott and Hort! Not only does the KJV translate that incorrectly from the Greek in this verse; it also does so
throughout the entirety of scripture, even when it is clear the writer is not talking about the world ending.
The KJV teaches a bad eschatology.
The KJV also renders "
agape" as "
charity" (1 Cor. 13:4-8). This is well-known and easily corrected but the protectors of the KJV refuse to correct this mistake, even though the error is objectively apparent. The argument "charity" is synonymous with agape love is utterly false and appeals to what charity meant 400 years ago are likewise fallacious. Charity does not mean love. Since the greatest two commands God ever spoke are to love God and love others the KJV translation of 1 Corinthians 13 corrupts THE two greatest commands of God! Here again there is
no deviation among the Greek manuscripts.
The KJV teaches bad theology.
The KJV translation of Deuteronomy 33:14 says the bull's horns are like a
unicorn's! The
Hebrew never says any such thing. Not only does the KJV mistranslate and thereby misconstrue the bull's horns, but it also implicitly teaches the existence of mythical creatures (Hebrews of the Pentateuch did not believe in a thing called a unicorn. The "unicorn" was first mentioned centuries later in the 4th century, not in the 14th-13th when Moses wrote Deuteronomy).
In 1 Timothy 3:16 the KJV states "
God was manifested in the flesh," but the Greek is "
hos," (who) not "
theos," (God). Here there are some differences among the Greek manuscripts but not a single one of them says
theos. They ALL say
hos. Jesus is God, but that does not change the fact the KJV did not translate the Greek correctly in 1 Tim. 3:16.
In
Romans 8:6 the KJV translates the Greek "
sarkos," which literally means "
flesh" as "
carnal." The Greek literally states, "
mind of flesh," and there's no reason to translate the Greek other than as stated. Here again ALL the Greek manuscripts agree, and it is the KJV that has departed from the uniformity of the Greek. Not only does the KJV render the
sarkos incorrectly, but the KJV does not render Romans 8:6's
sarkos differently than all the other sarkoses used in scripture. The KJV is not even consistent with itself in Romans 8:6. It takes that one
sarkos and translates it differently than all its other examples!
The KJV teaches a bad hamartiology.
These are only a few examples of the many, many translation errors in the KJV. There are scores of them. The KJV cannot be fully trusted, and it most definitely cannot be trusted over the Greek. In every single one of these examples most of the modern translations are markedly, observably, objectively more trustworthy.