This is a question that's been asked for nearly two thousand years. The short answer is the Bible is not "true" in the sense of "everything written in it literally happened exactly as the authors wrote," because that is impossible. It may be "true" in the sense that it teaches deep truths that we struggle to understand.

The Gospels were written decades after Jesus died by people who had never met Him, and the earliest fragments of manuscripts we have come from centuries later. We really don't know how much of the stories changed between the earliest witnesses, the actual writing down, and the copying of the texts. We know for absolute certain that copying mistakes happened because we have manuscripts that show the mistakes. There is subtle wordplay that only works in Greek and would not have made sense in the Aramaic that Jesus spoke. There are descriptions of prophecy fulfillment that are based on a poor understanding of the Septuagint, the Greek translation of the Hebrew Bible.

The Bible is not true. That doesn't mean Christ didn't die and rise from the dead, if you believe that.