At the end of my copy of Fairest, there was an excerpt from Winter (the first 3 chapters). There was quite a bit of interaction between Jacin and Winter, and I could tell they loved each other. At this point, I think it's romantic love, but it could easily be the love of friends. Also, Jacin grew up with Cinder (Selene) and Winter, although he was closer to Winter because her father was friends with the Clays.
"I fear tomorrow will be even more difficult for you, Sir Clay. Do try to think of me when you can" "Try, Princess?" He smirked, meeting her gaze again. "I can't seem to think of much else."
"I fear tomorrow will be even more difficult for you, Sir Clay. Do try to think of me when you can"
"Try, Princess?" He smirked, meeting her gaze again. "I can't seem to think of much else."