A deposit insurance is a safeguard measure implemented in many countries to protect bank depositors, in full or in part, from losses caused by a bank's inability to pay its debts when due.
In Germany, the deposit insurance covers losses of up to € 100,000. For you and your blocked account, this means that the money in your blocked account will always be insured based on German law - 100% guaranteed!
☝ Of course, this does not cost you anything. The deposit insurance is already included and free of charge for your blocked account.