@esaiji
Well it's probably more of her transitioning from the one-in-a-dozen mindset to a "I'm not just another clone in the herd" mindset, so I can see where she's a little confused.
As for the promise, I'm pretty dang sure she assumed Melon was a pureblooded gazelle or whatever his dad is. So when he asked if he could eat her, she probably at least partially figured he was joking. I doubt she would have made that promise if she were aware of his carnivorous side.
But hey, I guess it's more motivation (and deadlines) for Legosi, especially now that Louis knows.