Nero and Ciri will both agree to sign a good Yelp review for him, even if Nero's will helpfully say something like "crunchy and wicked tasty." However, since he's made the guy almost cry -- and that's cringe heroic behavior -- he'll agree when Ciri offers for them to talk to Marcellus on the merchant's behalf. Hell, they'll even hand-deliver the Yelp reviews.