I dont know if it's just me, but I have not seen really any romantic interest between the two in the show. I dont know if I missed anything or I'm blind, but Suletta clearly likes the white haired boy and Miorine is just using Suletta to not be engaged with anyone who would use her for her power. Heck, the latest episode even hinted at Miorine and the long red headed boy having a past relationship, or him possibly having feelings for her.