>From my limited knowledge and understanding, I can only give a few tidbits of info to why I believe the KJV is a trustworthy translation, and others are less trustworthy.
1) the KJV translators were godly ethical men who translated the OT from Hebrew and the NT from Greek. All greek words have several versions that can apply to one word in english. The knowledgeable translators used the english word in each case that matched the Greek accounting for context and doctrine..and they had the Holy spirit and the witness of each other for confirmation.
2) they used the Antioch Syrian textus receptus to translate from, an uncorrupted manuscrip. The Synactus Alexandrian text was suspiciously corrupted and edited by less than scrupulous scholars who procured the scriptures fro their own editing and translating . Most of the greek lexicons in existence are based on the alexandrian version, and therefore the greek to english translations in them cannot be trusted.
3) There are biblical truthes in the KJV  that common sense and cross referencing prove that it is reliable and preserved by the will and intervention of divine promise. These truthes and cross references are/ will be distorted, confused and sometimes destroyed in the modern versions translated from corrupted greek.
Examples below:

Gal 2:20 KJV "20 I am crucified with Christ: nevertheless I live; yet not I, but Christ liveth in me: and the life which I now live in the flesh I live by the faith of the Son of God, who loved me, and gave himself for me.

Gal. 2:20 NIV " I have been crucified with Christ and I no longer live, but Christ lives in me. The life I now live in the body, I live by faith in the Son of God, who loved me and gave himself for me. 21 I do not set aside the grace of God, for if righteousness could be gained through the law, Christ died for nothing!”[e]

You can see that it says " l live by faith "IN" the Son of God" in the NIV..by the context and truth we know, the KJ says "the life which I NOW live in the flesh, I live by the faith OF the Son of God"...we know that we who are indwelt by the Holy Spirit have the Faith imputed to us by HIM indwelling us..we are not living by our own faith..it is a "gift of God" Eph.2:8

Gal.3:1, 2  KJV " 1 O foolish Galatians, who hath bewitched you, that ye should not obey the truth, before whose eyes Jesus Christ hath been evidently set forth, crucified among you?

2 This only would I learn of you, Received ye the Spirit by the works of the law, or by the hearing of faith?


Gal. 3: 1, 2 NIV "1 You foolish Galatians! Who has bewitched you? Before your very eyes Jesus Christ was clearly portrayed as crucified.2 I would like to learn just one thing from you: Did you receive the Spirit by the works of the law, or by believing what you heard?


Note that the KJ says" Jesus Christ has been evidently ( evidence was sure) set forth, crucified among you" ..and" did you receive the Spirit by law, or hearing by faith"

The NIV says Jesus was merely "portrayed" as crucified..and Did you receive the Spirit by WHAT YOU HEARD ? For all the reader knows, that could be anything !


Eph.1:10 KJV " That in the dispensation of the fulness of times he might gather together in one all things in Christ, both which are in heaven, and which are on earth; [even] in him:


Now we know this says that all who are "in Christ" ( saved) will be gathered in the fulness of times..hence, after all enemies have been subdued at the end of the Millennium reign of Christ.


Eph.1 :10 NIV "

to be put into effect when the times reach their fulfillment—to bring unity to all things in heaven and on earth under Christ.


Gee, that really explains it ! That does not imply when, why or who.



Heb 10:23 KJV " Let us hold fast the profession of [our] faith without wavering; (for he [is] faithful that promised;)


Now if this epistle was indeed written to Jews and Proselytes(converts) in the tribulation period, as I believe, then as a confirmation of OT Prophecy, they will have to endure to the end, and be justified by THEIR OWN FAITH AND RIGHTEOUSNESS. This verse in KJV supports this. Now, in this dispensation of grace, we are justified by faith OF Christ and sealed, a non-remittance of losing ones salvation ( Heb.6: 4-6)


Heb.10: 23 NIV " Let us hold unswervingly to the hope we profess, for he who promised is faithful.


Oh that explains it so clear ! NOT !


So you can see from these few examples that modern versions are unrelibale and at best give a watered down picture of the whole truth of the word of God, and at worst are a dangerous deception and diversion from the truth. Some versions are not as bad, but do you really want to take that chance? Wouldn't you rather bear the King's English and trust not to be possibly deceived ?