I don't know how people's can borrow lump sum amount of money from other without having any idea how to pay that back in future.

I don't know how people's can borrow lump sum amount of money from other without having any idea how to pay that back in future. I cant even imagine in my nightmare taking 100 bucks from someone and not being able to pay within a week in max, I would probably go in the depression if someone owes something from me.