@tuatara1
The manga seems like it's starting to deviate from the novels somewhat. Heroine is explicitly described as a genuinely nice person (when Mc isn't around), which is a major improvement over the one-dimensional racist brat we get from the novels. (I say "racist" because people with dark hair are treated like a separate race in the kingdom for plot-related reasons.) We also get a justifiable reason for the Heroine's fear of MC, which stems from MC's aura and power rather than the stigma regarding her black hair.
To a superstitious commoner, a black, hazy blob of scariness and power would certainly look "evil", after all.
While the Prince is still somewhat cautious of MC, he realized earlier on that Mc cannot be the Demon Lord (because said entity is both Male and a pre-existing entity), and he clarifies that to the Heroine early on as well.
Fingers crossed, but this manga MIGHT end up better than the novels as long as the artists correct the
overwhelming stupidity and lack of character depth that had so many novel readers cringing constantly in the comment section.