In christianity do you believe that everyone goes to heaven and what's the point of having hell?
No, we don't believe everyone goes to heaven; some people go down to hell. The point of hell is punishment for sins.
In Christianity we believe that either you pay for your sins in hell eternally (ie forever), or Jesus - who is the incarnation of the
eternal God - pays for your sins instead.
Everyone has sinned: Christian, Muslim, Jew, etc. That means, there are some sinners who get their sins paid for (Christians), and there are some sinners who have to pay for their sins themselves (everyone else). Either way, all sins are paid for. It's just a question of who pays.
If I convert to Islam, I would stop believing that Jesus is God and I would stop believing that my sins are paid for. What do I get instead?
A Muslim told me that on Judgment Day, there is a scales. If your good outweighs your bad, you go to Paradise. If your bad outweighs your good, Allah ****s you to hell forever.
Does that mean you believe a good Christian can go to Paradise, along with Muslims? Or a good atheist?
In Christianity, we say there is perfection, and there is evil. If your scales are not perfect on that day... hell. We rely on a scapegoat instead, basically.