If you are lost in the desert, you know you are saved when you are no longer ACTUALLY lost in the desert.
Many a slip 'twixt the cup and the lip, as they say -so just keep doing that which leads to being saved EVENTUALLY.
If one day you find yourself no longer human -immortal -and not in the lake of fire... you're saved.
However... the fire is actually meant to save the rest! Not all realize that!
God is ABLE to destroy both body and spirit in Gehenna, but that does not mean that is what he WILL do.
He is also able to use it as an ultimatum/last resort/final purification for those who did not respond to anything else.
1 Cor 3:13Every man's work shall be made manifest: for the day shall declare it, because it shall be revealed by fire; and the fire shall try every man's work of what sort it is.
14If any man's work abide which he hath built thereupon, he shall receive a reward.
15If any man's work shall be burned, he shall suffer loss: but he himself shall be saved;
yet so as by fire.
THOSE will know they are saved when they are no longer in the fire!
1 Cor 15:20But now is Christ risen from the dead,
and become the firstfruits of them that slept.
21For since by man
came death, by man
came also the resurrection of the dead.
22For
as in Adam all die, even so in Christ shall all be made alive. 23But
every man in his own order: Christ the firstfruits; afterward they that are Christ's at his coming.
24Then
cometh the end, when he shall have delivered up the kingdom to God, even the Father; when he shall have put down all rule and all authority and power.
25For he must reign, till he hath put all enemies under his feet.
26The last enemy that shall be destroyed is death.