Now when He was in Jerusalem at the Passover, during the feast, many believed in His name, observing His signs which He was doing. But Jesus, on His part, was not entrusting Himself to them, for He knew all men, and because He did not need anyone to testify concerning man, for He Himself knew what was in man.”
‭‭John‬ ‭2:23-25‬ ‭NASB1995‬‬
This is an important warning: many believed in Jesus, yet He didn't reveal Himself to them; He didn't allow them to come to know Him in truth. This should concern all who believe that knowing Jesus more and more is the greatest thing in life (Philippians 3:8). 
It made me wonder, to whom does Jesus entrust Himself
The next two chapters detail two conversations which the Lord used to help answer this question a bit: one with a learned religious leader, and the other with a Samaritan woman five times divorced. Jesus chooses to entrust Himself to one of these, but not the other. Surprisingly, Jesus does not entrust Himself to the religious scholar; but He does reveal Himself to the undeserving woman. 
It’s helpful to compare the two conversations, and to ask the Lord for light: why did You reveal Yourself to the divorced woman, but not to NicodemusWhat did You see in each of them, that led You to withhold in one case, and entrust in the other? I was blessed to consider just one answer to that question. I’m sure there are many other answers and differences that the Lord will reveal to humble, hungry hearts. 
Notice the difference in how Nicodemus and the woman respond to Jesus’ words:
Jesus answered and said to (Nicodemus), ‘Truly, truly, I say to you, unless one is born again he cannot see the kingdom of God.’ Nicodemus *said to Him, ‘How can a man be born when he is old? He cannot enter a second time into his mother’s womb and be born, can he?’”
‭‭John‬ ‭3:3-4‬ ‭NASB1995‬‬
Jesus answered and said to (the woman five times divorced), ‘Everyone who drinks of this water will thirst again; but whoever drinks of the water that I will give him shall never thirst; but the water that I will give him will become in him a well of water springing up to eternal life.’ The woman *said to Him, ‘Sir, give me this water, so I will not be thirsty nor come all the way here to draw.’”
‭‭John‬ ‭4:13-15‬ ‭NASB1995‬‬
I was struck by this difference only as I continued reading Jesus’ conversation with Nicodemus. One phrase in particular stood out: “Do not be amazed that I said to you, ‘You must be born again.’”
‭‭John‬ ‭3:7‬ ‭NASB1995‬‬
I Must Be the One in Need
Whereas the woman at the well received Jesus’ words for herself, as the one in need, Nicodemus received Jesus’ words as general instructions for people, useful things for “a man” to know. And Jesus corrected him for it: “I’m talking to YOU. Don’t be surprised I said TO YOU that YOU must be born again. You’ve got questions about ‘a man.’ Don’t ask about ‘a man;’ ask for yourself. Come to Me because of YOUR OWN need.”
In the world, when someone is embarrassed of a need they have, they veil their intentions by “asking for a friend.” “I know somebody who...” needs such and such. "What would you say to that man? Not me, but a friend. Someone I know..."
In spiritual matters, there’s a grave danger of listening for a friend. “I know somebody who needs to hear that...” “Ohhh, that’s the perfect argument for so and so.”
And what happens is, the Lord does not entrust Himself to such a one, who comes to Jesus with a question for a friend, with the attitude of self-sufficiency. One may leave such a conversation with a better grasp of a technical truth, and yet walk away without coming to know The Truth, Jesus Christ Himself, more fully. That’s because Jesus does not entrust Himself to those who aren’t needy themselves, but merely come to Him to have an argument for another. 
I was challenged by this simple example to be wary of ever “listening for a friend,” so to speak. Of accumulating arguments, rather than receiving life-giving instruction that meets my present need, that speaks to my present lack. I’m reminded of the rich young ruler as well, who came under the pretense of his own need, yet when the Lord lovingly pointed out his lack, he walked away grieving (Mark 10:21-22). He didn’t really believe he had a need himself. 
I want to remain in the spirit of the publican, “God be merciful to me, THE sinner” (Luke 18:13). I’m the one in need. I’m not asking for a friend. Give me this water so that I won’t be thirsty! 
I am encouraged to see that, no matter what the disqualification, as we see in the woman at the well, the Lord delights to meet such people, who are honest about their own need and deal with the Lord as the One Who wants to speak to them about them, not about others. To such, He gladly reveals Himself: 
I — Who speaks to you — am the Messiah.” 
- John 4:26