“Do you believe that if a person thinks they will be married to their wife in heaven, that they can’t be saved?”
I’m not a Mormon. Marriage in Heaven is a central tenet of the Mormon belief. It is not a debatable matter to them. It is a debatable matter to us.
Marriage MUST exist in Heaven for Mormons. You cannot be a Mormon and reject marriage in Heaven.
For Protestants, Jesus must be God in order for Salvation to work. You may not understand it but still be Saved. You cannot outright reject the Trinity and still be Saved.
Interesting distinction between ignorance and willful belief.