Thanks, 3sillydogs.
Yes, her maiden name was Botha - and, just to confuse matters even further, some Bothas married their Botha cousins - I have a few of these interfamilial marriages in my tree.
And I have seen those trees on familysearch, and trees on other websites, including Joe Botha's "Botha in Southern Africa." But I always try to verify everything, because you never know which trees are just including info from other online trees - and very few trees include sources or supporting evidence.
I do have the 1840 DN of Theodorus Ernst Botha - but wish I could find a DN for his wife Gesina Elizabeth van Rooyen as she apparently died 1875, so her DN may have included the married name of their daughter Gesina.
Gerhardus Petrus Pretorius was married to Gesina Elisabeth Jacoba Botha (I have verified that) - but I am not convinced that she was the daughter of Theodorus E Botha & Gesina E vRooyen.
Firstly, because "my" Gesina's name is "Gesina Elisabeth" in her will, her 2nd marriage record, and the DNs of both her 2nd husband and her father -
not "Gesina Elizabeth
Jacoba"
And, secondly, because, if you follow the Dutch/Afrikaans naming traditions, then the names of Gesina's 3 children from her first marriage would certainly point to Theodorus E and Gesina vRooyen being her parents.
The search goes on ... and it's driving me nuts