Not a fiance visa, but a long stay family visit visa under type of L. But in order to get your marriage registration in China, you can apply for a tourist visa (also L, but with 30 days duration in general) to enter China first. For the single/non-marital status certificate, 1. You need an Affidavit of Single Status, signed before a notary public.
2. Certified by the Secretary of the State Office of the state where the document is executed.
*Some states require the notarized document to be sent to the notary public's county clerk for verification before presenting to the Office of Secretary of State. Please contact Secretary of State Office of the state where your document is executed for details.
3. Certified by the relevant Chinese embassy or Consulate General over the area of your residence. The regular processing time at Embassy/consulate general is 4 working days.