I don't have an exact match for a Rebecca Fonda (1811-1844) who married a Henry Groesbeck but there are a few possibilities if some of your data is not quite correct. None of them appear to have been born or lived in Saratoga County.
1. Rebecca Vandenberg FONDA (1806- ) no marriage info. bp. Cohoes, Albany Co., NY
http://worldconnect.rootsweb.com/cgi-bin/igm.cgi?op=GET&...2. Rebecca Becker FONDA (1807- ) no marriage info. bp. Mayfield, Fulton Co., NY
http://worldconnect.rootsweb.com/cgi-bin/igm.cgi?op=GET&...3. Rebecca Bogaert FONDA (1789-1855) no marriage info. b. Albany, Albany Co., NY
http://worldconnect.rootsweb.com/cgi-bin/igm.cgi?op=GET&...4. Rebecca Groesbeck FONDA (1787- ) no marriage info. b. Schaghticoke, Rensselaer Co., NY
http://worldconnect.rootsweb.com/cgi-bin/igm.cgi?op=GET&...5. Maria Groesbeck FONDA (1775-1845) m. Abraham GROESBECK b. Schaghticoke, Rensselaer Co., NY
http://worldconnect.rootsweb.com/cgi-bin/igm.cgi?op=GET&...her mother is Rebecca GROESBECK (Maria is the sister of #4)
If you do in fact have a new person identified, please get back to me.
Regards,
A. Mark Fonda