The bible tells us about the many times Jesus revealed himself to his desciples in various occassions to confirm by himself the resurrection and we all know the significance of eyewitnessess for significant events that't why for example they are more journalists that cover specific events than others and the more witnesses we have the more we can trust the information about that particular events.
God made sure from the birth of Jesus that everything would be public and many groups of people would witness his birth,baptism,miracles,teachings,entering Jerusalem,his anointing with oil,last supper ,crucifixion and the glorious resurrection.In addition to the bible we have historians who have documented these events so people can safely believe them.Since this salvation message is critical so Jesus did everything to make it entrusted and that is why we have 4 gospels instead of one.According to torah so it takes 2 or 3 witnessess to judge in a case but Jesus goes beyond that and makes them 4 who tells the good news and the story of Jesus and according to the bible Jesus revealed himself to at least fivehundred people after his resurrection and that is why he used forty days on earth until he ascended to heaven to make sure that enough people had seen him personally so they would be his witnessess to the whole world with confidence.
But what makes believing in the resurrection possible even without any witnessess is it's power to perform miracles here and now,the answers to the prayers and the signs and wonders that accompanies those who believe in him.
I personally from childhood have been brought up in the christian faith and never doubted any thing in the bible and although I have gone through more difficult issues than most christians would go through normally but I have never doubted God or his goodness and because I have developed a great measure of faith through the years and known God intimately and his charachter in different situations that makes me trust him always and know that all things will work for my good at the end for his glory and the advancement of the gospel.
When we know God ,his characters and his works from creation and through
thousands of generations and his faithfulness to fulfill his promises we know that
every word that comes out of his mouth and every verse in
the bible is true.