John 20:29 Jesus encourages those who believe in Him without ever having seen Him. We believe other historic figures were alive because there were people who saw them and wrote about them. Same thing for Jesus. He was with certain groups of people and His stories have been told over and over again throughout generations. I believe the Bible and I know without a doubt that Jesus is who He says He is.
Jesus would not just ask for me to believe in Him by those words. He wanted to be in my heart as well, so I allowed Him in. If I weren't absolutely certain before I let Him in, I was absolutely certain after Jesus came to live in my heart. Because Jesus is VERY REAL, I see things in my life differently, I handle pain and suffering differently, I am more compassionate to others, I can "see" things more clearly for myself and others. I discern things because Jesus wisdom helps me. How can I have the wisdom of Jesus? Read His word, Pray, Listen for His voice, Keep a clear conscience, do unto others........