"Is it hard to believe?"

​Is it easy to believe, or is it hard to believe?
It’s so hard that it’s impossible to be the whoever, the whosoever, unless,
Joh 3:5  Jesus answered, "Truly, truly, I say to you, unless one is born of water and the Spirit he cannot enter into the kingdom of God.
To see the kingdom of God, to enter the kingdom of God - something must happen to you, and that culminates in belief.

To believe is more than a moment of assent.
More than an emotional moment.
More than a moment, years ago.
In fact, it is quite plain what it is to believe.
John tells us, in chapter 1, verse 12:
Joh 1:12  But as many as received Him, to them gave He power to become the sons of God, even to them that believe on His name:
To believe, is to receive.
To not believe, is to not receive: Joh 1:11  He came to His own, and  those who were His own did not receive Him. 
John equates “believing on His name” with “receiving Him.” 
Essentially, the same.
Meaning, to take (often, literally), to get hold of.

“I believe in God” is not John 3:16.
To believe – unto salvation – is a heart transaction, it penetrates.
Rom 10:10  for with the heart a person believes, resulting in righteousness, and with the mouth he confesses, resulting in salvation. 
Jesus must be received to be believed.
And that is a sovereign work of God, impossible with man.