@Desirious of Change.
90% of scholars who publish in this area (skeptic and Christian) agree on the following minimal facts:
1. Jesus was crucified by the Romans. Habermas said that this is "not an evidence for the resurrection, but it's a pre-requisite."
2. The disciples had experiences that believed were appearances of the risen Christ.
3. Because of their insistence that they saw Him risen from the dead, they totally changed in disposition from being afraid to being bold and unstoppable. They proclaimed, not just any message, they proclaimed the resurrection message and were persecuted for their proclamation. Habermas notes, "A number of them died for their faith. They were totally transformed and willing to die for their faith."
4. This proclamation of the resurrection was there at the very beginning of the Christian movement — it was not some later add-on.
5. One of the earliest to believe in the risen Jesus was the formerly skeptical James, the brother of Jesus.
6. Another skeptic changed by claiming he saw the risen Christ was the Apostle Paul, formerly Saul of Tarsus, the anti-Christian persecutor.
Again, these six facts are generally agreed upon by scholars of early Christianity, both friendly and hostile scholars to the faith.
From these, we see a clear pattern. Jesus died on the cross. Then His disciples, who were scared for their lives, suddenly changed into bold witnesses for the risen Christ. Nobody dies for something they know is a lie.
Other reasons to believe using non-biblical sources can be found here:
https://www.wordonfire.org/articles/fellows/four-reasons-to-believe-jesus-was-really-crucified/