@Sinobali it's my understanding that that is how basically all Kanji are. Different readings and whatnot. I'm not sure what other readings it has that could be a girl's name, but that's at least (sorta) an explanation.
@Danglark
Yamada is a dork, but she's not dumb.
She's well aware that she's hot af and that Ichikawa is a social outcast - the manga focus on the fact that she falls in love knowing that.
But the scene made Ichikawa looks miserable nonetheless.
@giolleau I mean it should be pretty obvious to anyone that ichikawa is a social outcast, for yamada too of course, but this manga is all about showing characters impressions of things and their feelings without really telling them, and now that I think about it they haven't really showed any hint of yamada actually aknowledging ichikawa as a weirdo/outcast until now (or maybe they did but I can't remember lol)