In John's Gospel, Jesus sometimes tricked those who opposed him, by using double meanings that left his opponents confused. John 3:1-13 is an example of this. The trick depends on two of the quite different meanings that ἄνωθεν (anóthen) can have in the Greek language:
Strong's 509: from above, from the beginning, again
Tom Thatcher says ('The Riddles of Jesus in Johannine Dialogues', Jesus in Johannine Tradition, page 275) the Greek term anóthen is intentionally ambiguous, as it can reasonably mean 'again' or 'from above'. Nicodemus chooses the former, but the correct answer is 'from above', which here establishes the difference between 'born of flesh' and 'born of spirit'. He says it is doubtful that Nicodemus could understand Jesus' elaborate answer (John 3:11-21). I would add that this entire riddle could not have taken place in Aramaic.
When Jesus says (John 3:3) "Except a man be born anóthen, he cannot see the kingdom of God," he means born from above, but Nicodemus interprets Jesus as saying he must be born again. The translators of the New American Bible recognised this, and managed to convey the meaning:
John 3:3-4 (NAB): 3 Jesus answered and said to him, "Amen, amen, I say to you, no one can see the kingdom of God without being born from above."
4 Nicodemus said to him, "How can a person once grown old be born again? Surely he cannot reenter his mother's womb and be born again, can he?"
The translation into English is difficult, and other Bibles consistently use one meaning for anóthen, or the other, as does the KJV:
John 3:3-4 (KJV): 3 Jesus answered and said unto him, Verily, verily, I say unto thee, Except a man be born again, he cannot see the kingdom of God.
4 Nicodemus saith unto him, How can a man be born when he is old? can he enter the second time into his mother's womb, and be born?
To the amusement of the Greek-speaking reader, Jesus repeats that a man must be born from above, and again Nicodemus is confused:
John 3:7 (NAB): Do not be amazed that I told you, 'You must be born from above.'
Finally, in John 3:13 we see clearly in the English language that Jesus was talking of being born from heaven above, even as he had been:
John 3:13 (NAB): No one has gone up to heaven except the one who has come down from heaven, the Son of Man.
John 3:13 (KJV): And no man hath ascended up to heaven, but he that came down from heaven, even the Son of man which is in heaven.
In this passage, Jesus is certainly talking of the need for faith, as we can see in verse 11, where Jesus accuses the Pharisees of not accepting his testimony and then, most importantly, in verse 15:
John 3:15 (NAB): so that everyone who believes in him may have eternal life.
Jesus was telling Nicodemus he must be born from above - a spiritual birth - perhaps "born again", but not literally as Nicodemus had thought:
John 3:6 (NAB): What is born of flesh is flesh and what is born of spirit is spirit.