Do you believe all Christians will go to Heaven. If one believes in Jesus being the son of God, will that person go to heaven, in your faith, no matter how sinful he was in his life?

No... i believe there are a lot of people who say they are christians and will not go to heaven. It takes A LOT more than just believing in Jesus being the son of God.. even the devil believes and knows who Jesus is and you won't see him in heaven...

I believe it doesn't matter what sin a person did in their past.. when they truly give their heart to the Lord... they come into repentance.. then they are saved and will go to heaven.. (i am not sure of the exact wording) but the Bible says that a persons joy will turn to sorrow when they are saved.. because they will be so sorrowful for the things they have done in their past... that they will morn for it.