This is the answer I gave them:
People come down to this earth, as human beings, to work on their spiritual side, aka eternal souls, and to fix whatever needs fixing.
At the end of a person's life, the body dies and decomposes, while the soul goes back to Heaven, to get it's report card.
Here's the thing: ALMOST EVERYONE IS GOING TO SPEND SOME TIME IN PURGATORY.
What I'm about to tell you is the Jewish take on purgatory, or what you're calling 'hell', which is VERY different in a number of notable ways, from the Xtian version, as follows:
1) Purgatory is just a big, spiritual clean-up operation.
When a person does bad things, it damages and stains their souls, so purgatory just comes to clean those stains off.
2) Apart from a few exceptions, Jewish purgatory doesn't last for more than 11 months - so it's not a permanent, eternal thing.
You pay your dues for the stuff you did wrong in purgatory, and then you get released and all the rewards you amassed throughout your lifetime are waiting for you in Heaven, for you to enjoy for eternity.
3) Purgatory only works to take care of the sins that are between you and God. The sins that you did against your fellow man CAN'T BE FIXED IN PURGATORY - they can only be fixed by your soul coming back down again, and making amends to whoever you hurt / stole from / double-crossed the last time around.
4) There are actually far worse punishments for a soul than purgatory (but that's a post for another time…)
5) Souls are MUCH happier with a short spell in purgatory than they are having to be reincarnated again.
While it's 'hell', it's still a spiritual experience and the soul knows exactly what's going on, and why. It has clarity. Down in this world, spiritual clarity is very hard to come by, and people can and do forget about their spiritual purpose all the time, and end up making even more mistakes and errors that require even more fixing.
So compared with being reincarnated as 'Bill' in Idaho for 80 years, who could continue to make a whole bunch of additional mistakes and fail to clean up all the stuff he was sent down here to work on the first place, an 11 month stint in hell followed by eternal bliss can often look like the better option.
If you have any questions for Talk to God, get in touch, and we'll do our best to answer you in a useful way.