First of all, you call the notary office to verify the number of the notarial certificate. Just say yes. Entrust the notarization wholeheartedly to yourself, the notary office, do a real notarization ISBN false notarization, and avoid others.
As long as the second house is transferred to your name, even if there is fraud, the property belongs to you according to the principle of "public trust" in the property law. Even if it is an understandable legal dispute, the property owner always gives priority to it.
Third, the responsibility for fraud and negligence, in any case, the price paid by honest buyers does not bear any responsibility and risk.