CENOMAR takes longer to get (not like the birth cert or marriage cert which u can get upon request), coz they have to verify it that one is not really married. They usually released it 3 weeks after the application. This is what i got from NSO website:

* The processing time is shorter when the copy requested is for a document that is already "converted" - i.e., the document is already in the CRS database.

* The processing period for requests for the Certificate of No Marriage Record is longer than that for copy issuance requests. The period could be longer if the surname of the subject person is common such as Aquino, Ferrer, Cruz, De Guzman, and others.

If u r going to get married here, cenomar is not needed.