Why are they forcing Amy as the love interest? Her problem is not a bad personality, but she's a bad person, period.
My gripe with her isn't even that she's necessarily a bad person (I don't think she is, though I still dislike her) but that there is NOTHING that should've lead the two together other than a series of misconceptions, and even then its pretty flimsy. I mean, from Shirone's perspective this is someone who's given him childhood trauma, went out of her way to bully him when he finally lifted his head up and entered the academy, and even when "reconciled" made up a lie that lead to him being ostracized by his class and did nothing to help. Yes, there was that whole thing about "competing fairly", but I fail to see how that could lead to romantic feelings. I thought the characterisation for shirone was that he's a meek, well-natured saint, not a moron.
And likewise for Amy, too. This is someone who's a commoner (actively shown to be HEAVILY discriminated against, considering the whole issue with being friends with Rian) and an initial liability. There is NO reason why she should suddenly develop feelings for this guy other than his good looks.
And that seems to be it; they're both physically attractive. And whilst yes, this IS something that can happen in real life, but it nonetheless feels contrived in a written setting because no one wants to admit to a love based almost purely, against all other factors, on physical attraction.