Hello Moe,

please note, that Marianne will most likely be written with on "r" in German.
Via Ancestry I found the marriage of Manuel Dinkel and Röschen (Rosa) Nussbaum Frankfurt / Main 1893 No 605.
It says that his parents are Jacob Dinkel and Marianne geborene Neuburger, (says Neuburger, not Neuberger) both living in Unsleben.

Next step is the village of Unsleben
Unsleben has a website on the historical Jewish Life in the Community and you'll also find information on the cemetry via
http://judaica-unsleben.de/cemetry/tombstones/

Probably this is her tombstone:
http://judaica-unsleben.de/project/bradnclus-hanhchen-e-19/
Search Dinkel, - Stone E-19
died July 15th 1899, 68 yo - born about 1831
says she was born in Wüstensachsen,  about 26 km from Unsleben (Bavaria)

There should also be a civil record of her death - I don't know the region and where it is kept, probably at the the State Archives of Wuerzburg.
I would ask the local administration /community where the documents are kept:
poststelle@...

More about the Jewish community in Wüstensachsen, Fulda (Hesse) - unfortunately not in English
https://www.alemannia-judaica.de/wuestensachsen_synagoge.htm

Jewish registers in Wüstensachsen (Hesse has the still existing Jewish registers online)
https://arcinsys.hessen.de/arcinsys/digitalisatViewer.action?detailid=v3282891
you may find her birth registered there (yet doing a quick review I didn't find it)

Good luck with your further research and regards from Germany

Corinna Woehrl
Hoisdorf, Germany (between Hamburg and Luebeck)