In fact, the intermediary's duty is only to accept the entrustment of both parties to the transaction and assist in completing the transaction, including assisting in completing the contract and submitting materials.
However, whether to lend or not, whether the loan is successful or not depends on the credit of banks and individuals, as well as the condition of the house. These intermediaries can't guarantee it.
Loans are not the responsibility of intermediaries. For example, if the buyer has a credit stain and can't get a loan, it won't be blamed on the intermediary.
If you are in doubt about whether you can get a loan
Remarks can be added to the contract: if the loan cannot be obtained, the contract can be terminated, and the buyer can refund the down payment in full and pay only half of the agency fee.
I hope it helps you.