There are two persons named "Berte Johannesdatter" mentioned in the 1801 Census; see:
https://www.digitalarkivet.no/census/person/pf01058348002720 (married to Ole Omundsen Rusdal); and
https://www.digitalarkivet.no/census/person/pf01058348002015 (married to Lars Torsen Gursli).
According to "Lunds historie" they are both referred to as "Berte Johannesdatter Osen".
According to "Sirdal bygdebok", Johannsen Bjørnsen Osen II had two daughters named "Berte Johannesdatter", one baptized 06-01-1753, married to Ole Omundsen Rusdal; and another baptized 06-01-1757, still alive in 1770, but fate unknown.
See https://www.nb.no/items/77c60739b529aa5e7ddf70e0f4525809?page=161.
Marriage record for the older sister (16-11-1774):
Lund sokneprestkontor, SAST/A-101809: Ministerialbok nr. A 3, 1761-1801, s. 458-459
Brukslenke for sidevisning: https://www.digitalarkivet.no/kb10511104150159
Marriage record for the younger sister (October 1779):
Lund sokneprestkontor, SAST/A-101809: Ministerialbok nr. A 3, 1761-1801, s. 462-463
Brukslenke for sidevisning: https://www.digitalarkivet.no/kb10511104150161
THUS: The "Berte Johannesdatter Osen" that was married to Ole Omundsen Rusdal IS NOT the same as the one that was married to Lars Torsen Gursli.