The marriage record for James O. Humphries and Sarah Ann Simpson in Tuscaloosa Co. Alabama reads "Humphries, James O. & Sarah Ann Simpson, 4 Nov. 1859 (6th) at res. of Wm. Simpson, who consents for dau."
Gandrud, "Alabama Records, Volume 3 Tuscaloosa County," p. 74.
So James Humphries of Alabama definitely married somebody named Sarah Simpson. Whether she is the daughter of Darling and Elizabeth Simpson of Chester Co., SC is what would seem to be at issue, then.
If you read things posted on the web, people seem to have believed this is true, but maybe it isn't.The Alabama marriage record indicates that Sarah's father was living in Tuscaloosa County at the time of her marriage (given that it says she was married at his residence).So is William Simpson who was living in Tuscaloosa Co. Alabama in 1859 the same man who married Bennett Humphries's daughter Elizabeth and who was shown in her father's will as "Darling Simpson?"
If not, that would be a good myth to bust.
How about evidence for the other side?Is there a marriage record or other relevant records that support the idea that Sarah, daughter of Darling and Elizabeth Simpson, married Asa Darby? We might be able to compare claims.
Bennett Humphries's nephew Charner Humphries married a Darby, so if the above is true, it would not be the first Humphries family-Darby cross.
Maybe other people have relevant facts to share. If so, it would great to see them.