In the first Ethel fight you need to let her take her turn when she's at like, 10-15% HP and she'll offer to give you power (+1 to any stat) if you let her and Mayrina go. If you pass a high intimidate or deception roll you can save Mayrina and get the buff. (Warning though: doing this breaks paladin oath if you care)
And for anyone who wants to cheat it on a paladin just make sure someone else is closer to Ethel than your paladin. Doesn’t count as breaking your oath if someone else does the conniving. Also she starts the conversation with the closest person. Make sure you change the auto select character after combat to off in settings or this will all have been for naught.