Most assuredly, I say to you, We speak what We know and testify what We have seen, and you do not receive Our witness.
If I have told you earthly things and you do not believe, how will you believe if I tell you heavenly things?
No one has ascended to heaven but He who came down from heaven, that is, the Son of Man who is in heaven.
And as Moses lifted up the serpent in the wilderness, even so must the Son of Man be lifted up, that whoever believes in Him should not perish but have eternal life.
For God so loved the world that He gave His only begotten Son, that whoever believes in Him should not perish but have everlasting life.
For God did not send His Son into the world to condemn the world, but that the world through Him might be saved.
[John 3:11-17 NKJV]
Verse 11 is the third time in John chapter 3, that Jesus uses the expression “most assuredly”*. He speaks to Nicodemus (conqueror; victorious among his people), a member of the Sanhedrin and thus a man of learning and Jesus is ‘assuring’ and reassuring him of the Truth.
The passage quoted above is the more complex exposition resulting from Jesus’ talk of being born again, and contains what is possibly the most quoted verse in the Bible — John 3:16 — For God so loved the world that He gave His only begotten Son, that whoever believes in Him should not perish but have everlasting life.
Jesus is impressing on Nicodemus the incontrovertible veracity of every word He says — and using the expression three times in quick succession— as Jesus does here — is our guarantee that Jesus speaks from the throne of God.
Nicodemus is convinced — and we know this because He appears later in John’s Gospel (7:50, 19:39) as loyal to Jesus. John is building his case to show clearly to all that Jesus is who He says He is, and this piece is clearly aimed at the Jews; showing that a member of the Sanhedrin — the legal hierarchy; a high-ranking judge — finds the evidence for Jesus compelling, and most assuredly the truth. Jesus is new life.
* Most assuredly: translated in the King James Version as “Verily, verily” is an expression used 25 times in the Bible, but only in the book of John. It is from the word Amen, and the Hebrew אָמַן ’âman; a primitive root; properly, to build up or support; to foster as a parent or nurse; figuratively to render (or be) firm or faithful, to trust or believe, to be permanent or quiet; morally to be true or certain; once (Isa. 30:21; interchangeable with 541) to go to the right hand: — hence, assurance, believe, bring up, establish, + fail, be faithful (of long continuance, stedfast, sure, surely, trusty, verified), nurse, (-ing father), (put), trust, turn to the right.
Watch spiritual hardness, if ever you have the tiniest trace of it, haul up everything else till you get back your softness to the Spirit of God.