I tried to make a booking. I am required to have a credit card. I don't pay via credit card, I just have to demonstrate that in case I don't come to the hotel, they can take the fee equal to the price for the nights I would be there.
I chose a credit card I don't have much money on and it was rejected. They say they want to take 100€ from my credit card in order to verify I don't cheat. They will give me the money back as soon as they receive it.
What if they don't? Should I accept the transaction? Is it safe?