[Elsie]

What is the definition of "truly a Christian" and then we can go from there.

Well...

When Jesus was asked a direct question; He replied with a direct answer:

 

John 6:28-29

Then they asked him, “What must we do to do the works God requires?”

Jesus answered, “The work of God is this: to believe in the one he has sent.”

[GBA]

Seems straight forward enough to me, though I only speak for myself, of course.