About half of the world's Christians are catholics; the other half are protestants, orthodox (like in greek or russian orthodox), evangelicals, church of england (anglo-saxon). And even among the protestants, they're split into methodist, quakers, lutherans, calvinists etc.
As for the bible writers telling the truth. Yes, they did just that - according to their own nneds and to whom, e.g. what target group, for which they were writing. The Gospel according to Mark, we know now to have been written about 50 A.C. It is possible and likely that Mark actually lived at the same time as Jesus (Joshua) - and wrote his account on what happened, especially since the original ending didn't tell anything about the resurrection. This part were added later...