@Qelix : Now now... there are plenty of troubled, attractive, single women out there.
Problem is of course that while plenty of guys can't get into a relationship at all because nobody wants them... the equivalent problem for women is that the guys who DO want them... are trash. Domestic abusers, rapists, skeevy bastards, manchild types... etc. Basically just guys who would treat them like a mobile fuck-toy. Unsurprisingly, they tend to discount those entirely when considering their romantic prospects...
O'course Japan has its own problems. Weird consideration of age is one of them. Inability to communicate in clear, literal terms is another. Unwillingness to do anything that might be considered socially disruptive is a third. It is hardly surprising the population is in decline over there.
Plus she is a manga character and is deliberately drawn in an idealised fashion that is probably completely unrelated to how others actually see her within the narrative.