You ask the question, "Isn't the fear of hell needed to persuade people to be good?" The assumption of many people is that Christianity is about terrifying people in heaven. But that is the logic of Islam. In Afghanistan for example the Taliban are ruthlessly trying to bring people under the fear of God, but love is being squeezed right out of human hearts.
The logic of the love of God is quite different. It begins with "How can we make humans in our image?" (Genesis 1:26-27), and since God is love (1 John 4:16) the image of God is to love the way God loves.
You can make people obey laws by the heavy hand of government. But there is no way guilt or fear ever made people love the way God loves. Admittedly as children we have to learn the consequences of this and that kind of behavior. But there comes a point when we have to choose the love of others as opposed to selfishly abusing them. There also comes a point when we realize that without the inspiration of the Holy Spirit we cannot produce genuine love in our hearts. And at a deeper level there is an eternal choice of the light that Jesus brought into the world as opposed to preferring the darkness.
That is why John 3:16 is explained by "God did not send the Son into the world to condemn the world (John 3:17). But there is a judgment (the Greek word is krisis): "This is the judgment, that the light has come into the world, and people loved darkness rather than light because their deeds were evil. . . But those who do what is true come to the light, so that it may be clearly seen that their (good) deeds have been done in God (by the Holy Spirit of God)" (John 3:19-21).
We are not made good by the fear of hell but by allowing the Holy Spirit to change us for heaven.