Who has returned from that world to testify?

In the depths of the sea, there lived a dynasty of fish, of which a large number of members often disappeared, after they left for food.

All this continued for centuries in this dynasty at the bottom of the sea, The members watched daily as their neighbors, fellow citizens, relatives, and family members, young, old, disappeared without any explanation and never returned to them.

Among the inhabitants of this dynasty, there was also an old fish who was full of knowledge and wisdom that she gathered during her life, taught by the tangles that life weaves daily.

The old fish often gathered the other inhabitants of the dynasty and taught them, saying: "My dear fellow residents, when you see a piece of meat, a small fish, or an insect hanging on a transparent nylon wire, do not run after it, and do not under any circumstances eat it."

"It's a bait, and behind it is a terrible claw, which gets stuck in your mouth when you eat the bait, and then that claw pulls you up, above the surface of the water, and there is a creature there, which is huge and terrible, and he pulls the wire, then he catches you in a net and pulls you out of the water, then he takes you to a place where they cut you up, take out your organs, remove your head."

"After that, they took you to a burning fire and placed you in hot oil, which fried you so hard that your skin separated from your flesh; it was a great pain and punishment for your clumsiness and for failing the exam and always eating the bait!"

Don't! Indeed, behind that bait is a severe punishment that never ends; it only grows larger and larger!"

And the members of the dynasty always say after listening to her to the end: "Don't tell us stories, grandma, who came back from there so you know how it is?!

The question the fish asked is connected to the title. Who has returned from that world to testify?

No one will believe for real until its to late. We always have to stick to our beliefs, no matter there are doubter and people who will find their reasons.