If it is true that...

The historical existence of Jesus is quite certain

and

It is surprising to have certainty of any Judean's existence around Jesus's time

Then it must be true that...

There is something interesting about Jesus

If it is true that...

Many people gave their lives to tell others about Jesus

and

Others who claimed to be Messiahs did not have followers die trying to tell people about them

Then it must be true that...

There is something interesting about Jesus