I translate it as
On the 15th of November 1837, therefore, I married Cornelius Demare, (baptized by a Catholic) a dispensation of conception under the disparity of worship, and Delphine Keepers, a daughter of the marriage of James Keepers and Marie Elder, as witnessed by
Witnesses: Aloysius Keepers, Elisa Chandler, James Keepers, Mary Keepers and others
And then there is the signature of the priest beside the witnesses.
It means that Cornelius' parents were Protestant but that he was baptized a Catholic (converted to Catholicism) before the marriage, and that Delphine was the daughter of a legitimate Catholic marriage.
It definitely does not mean that Delphine was not a Catholic. The point of the two words "filiam ... conjugum" which state that she is the daughter of the marriage of her parents is to demonstrate that she was born a Catholic. Listing her that way with her parents shows she is entitled to be married in the Catholic Church. Cornelius, having protestant parents, had to be baptized by a Catholic priest as a condition of getting the dispensation to allow the marriage.
Delphine is a French given name. She was likely of French or French Canadian descent. There were a lot of French Canadians in Missouri around that time, including many of my husband's relatives.
A pretty common situation in the melting pot of Missouri in 1837.
By the way, the marriage record does not list Cornelius' parents as is stated in the profile.
And by the ancestry given for the Demare family in early New Jersey, I would think it was a good bet that his family were historically French Huguenots, protestant.
