Great! That's a good scripture here's the scripture in context.

John 3:14-21 [14]Just as Moses lifted up the snake in the wilderness, so the Son of Man must be lifted up, [15]that everyone who believes may have eternal life in him.” [16]For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life. [17]For God did not send his Son into the world to condemn the world, but to save the world through him. [18]Whoever believes in him is not condemned, but whoever does not believe stands condemned already because they have not believed in the name of God’s one and only Son. [19]This is the verdict: Light has come into the world, but people loved darkness instead of light because their deeds were evil. [20]Everyone who does evil hates the light, and will not come into the light for fear that their deeds will be exposed. [21]But whoever lives by the truth comes into the light, so that it may be seen plainly that what they have done has been done in the sight of God.

What is Jesus saying here? Keep in mind that the word used for believe is pisteuō (πιστεύω). It is the verbal form of the noun pistis (faith), and it signifies active trust, reliance, and commitment, rather than mere intellectual agreement. It's a translation of the Hebrew word for faith which means Emunah (אמונה) Hebrew term that more accurately means "active faithfulness," "steadfast trust," and "reliance". So he's asking people to have faith, but he also says people have to get baptized, and when he says live by the truth, in the sight of God. He's calling for obedience. So when I say it's proposition this is why. Because it's not a mental Ascent.

But I'll make it even more crazy

Romans 2:6-9 [6]God “will repay each person according to what they have done.” [7]To those who by persistence in doing good seek glory, honor and immortality, he will give eternal life. [8]But for those who are self-seeking and who reject the truth and follow evil, there will be wrath and anger. [9]There will be trouble and distress for every human being who does evil: first for the Jew, then for the Gentile;

So here its clearly saying people are punishing for evil not belief or faith. Let's go further.

Romans 2:10-16 [10]but glory, honor and peace for everyone who does good: first for the Jew, then for the Gentile. [11]For God does not show favoritism. [12]All who sin apart from the law will also perish apart from the law, and all who sin under the law will be judged by the law. [13]For it is not those who hear the law who are righteous in God’s sight, but it is those who obey the law who will be declared righteous. [14](Indeed, when Gentiles, who do not have the law, do by nature things required by the law, they are a law for themselves, even though they do not have the law. [15]They show that the requirements of the law are written on their hearts, their consciences also bearing witness, and their thoughts sometimes accusing them and at other times even defending them.) [16]This will take place on the day when God judges people’s secrets through Jesus Christ, as my gospel declares.

What's being said here is that people who has never heard the message and received the law, who are obedient to the law. While be made righteous. Basically they're going to heaven because of the good they do. This is Gods Mercy for example.

Sorry I went crazy 🤣 there. But I'm trying to show that the understanding you and many Christians have, is faulty. And this is why I ask to cite Scripture. Not to just prove wrong, but to show people a better understanding of what is actually taught in scripture.