There is much more to Christianity than belief or faith. It is a religion of doing and supernatural being. The doing is living the path of Jesus. The being is fully accepting personal integration with the Holy Spirit and conforming to ways of the New Creation which results from that integration.
Jesus said to love God the Father with all of your being and to love your neighbor as yourself. That’s it. Jesus said that these two items were the sum total of all of Christianity. Those are the commands of Jesus and the complete challenge of following Jesus on his path to salvation, new creation, and eternal life in God’s paradise. Following those are what it is to believe in Jesus. If you believe in Jesus you will need to actually believe Jesus and follow him according to what he teaches. Jesus said that few will accept this true way of faith.
John 15:12-17 (WEB)
12 “This is my commandment, that you love one another, even as I have loved you. 13 Greater love has no one than this, that someone lay down his life for his friends. 14 You are my friends, if you do whatever I command you. 15 No longer do I call you servants, for the servant doesn’t know what his lord does. But I have called you friends, for everything that I heard from my Father, I have made known to you. 16 You didn’t choose me, but I chose you, and appointed you, that you should go and bear fruit, and that your fruit should remain; that whatever you will ask of the Father in my name, he may give it to you.