Would there be less Christians if the realized hell was not eternal torment ?

I am still baffled by your statement of ''if the(y) realized [that] hell was not eternal'' As human beings we honestly no nothing of hell and if it were to exist we cannot have the assumption that it isn't eternal. Many non-Theistic religions do not believe in hell but most of those who believe in it also believe that it is eternal. Is there a teaching in the Christian Bible or doctrine that states that hell is not everlasting?