When speaking of the Jesus of history, you might want to tell people about the secular historic documents that speak of Jesus. All were early, mostly Roman, historians who documented events of their time. None were believers. These were Flavius Josephus, Tacitus, Mara bar Sarapion, Suetonius, The Babylonian Talmud, Pliny the Younger, and Phlegon of Tralles.

I believe that to reach nonbelievers, you need to start where they are at. Then, slowly bring them to an understanding of the truth of Christ. Of course, you also need to explain in depth that God is love. All they see of supposed Christians today are the hateful, mean spirited, heartless people who call themselves Christians.