Was Jesus a con artist?  Yes, if he did not rise from the dead as he said he would.  The backbone of every apostolic sermon was the resurrection.  It proved Jesus is the Son of God.  Our belief in the resurrection depends on the testimony of apostles and their associates.  Are they dependable witnesses?  A judge is confident in his verdict if he has multiple witnesses who agree, and more so if they are eyewitnesses, careful and not credulous, and are honest.

Many (over 500 at one time) saw Jesus alive.  The gospel accounts come from eyewitnesses or those who took down eyewitness testimony.  The apostles refused to believe until they had made certain.  They were honest, willing to die for their testimony, and many did.  People tell lies to get out of trouble, not to get into more trouble.  But these witnesses knew what they had seen and had to tell it.

Only the resurrection could have changed the apostles from cowards to courageous.  Saul of Tarsus exchanged one of the brightest futures in Judaism for a life of suffering because he met Jesus alive.  In the weeks and months after the crucifixion thousands of Jews became Christians knowing the danger to themselves and their families.  They lived where they could check everything out before risking all.  Ironically the strongest evidence is from the unbelieving Jewish leaders.  They hated the resurrection message with a passion.  If any hole could be found in the testimony, they of all people would have found it and stopped the gospel.  They could not.  The facts of the resurrection gospel have been tested as severely as any proposition in history.  We can depend on it completely.  It happened.