It is possible to reset all game settings on the Mac version of the game by deleting the settings file. It is stored at the following location depending on your store:
- Mac App Store: ~/Library/Containers/com.inxile.BardTaleOSX/Data/Library/Application Support/The Bard's Tale/
- All Other Stores: ~/Library/Application Support/The Bard's Tale/SavedGames
The folder can be accessed with Finder using Go > Go to Folder. From there, just delete the settings.bin file and that will reset all your in-game settings.