Legal analysis: Because you get a marriage certificate, the cost of buying a house is already a joint expense, so you must ask the other party to sign a notarial certificate to prove that the down payment is your separate expense and belongs to the property before marriage, and the later loan belongs to the joint property of two people.

Legal basis: Several Specific Opinions on Handling Property Division in the Trial of Divorce Cases by People's Courts Article 6 Property owned by one party before marriage, houses and other valuable means of production used, operated and managed by both parties after marriage have been eight years and valuable means of subsistence have been four years, which can be regarded as joint property of husband and wife.