I'm not so sure of Nina's lead. One thing making the situation so complicated is the fact Layfon himself doesn't really seem to be interested in romances. I suppose he considers them all his friends, but even his concept of a friend is someone whose safety he must protect at any cost, and that's it, more or less. I guess such a twisted view origates from his past as an orphan, who ended up protecting the other orphans at the cost of his own position as a heaven's blade receiver. Somehow I doubt he loved even Leerin back then when everything was still well.
In the end Layfon might be far more damaged goods than Felli. Although I'm kind of pleased he hasn't changed that much. Makes things more interesting, even if at the same time I wish he would get together with Felli.