"so you have faith and that is all you need"
Christianity is unique. Unlike all other religions, it is not based on blind faith.
Yes, Christianity requires faith, but it is an educated, fact-based faith. The historical record backs up what is written in the Bible. Even the key event in Christianity; the fact that Jesus was born, was crucified on the cross and three days later rose from the dead has so much historical evidence supporting it that even scholars who oppose Christianity have to admit it happened. It doesn't take faith to believe the Bible accurately records history.
Faith is not required to know Christianity is true.
So what is faith?
Because of our faith, a faith based on the character of God revealed in the Bible, we know that God's promises to us are true.