The Christian's joy is not based on physical circumstances or human relationships. We can rejoice even as we suffer in these physical ways. Our joy is based on spiritual circumstances: forgiveness of sins, our fellowship with God, and the blessings of serving Him and the hope of eternal life.
When someone does not believe in the Bible, Jesus, or God, how can we convince them? Should we use archaeology, science, logic, secular history? Yes, but examples in the book of Acts emphasize creation, miracles, fulfilled prophecy, and the resurrection of Jesus.