Ha! Called it that the confessing girl's only purpose was to reveal that her arrow shape means 'casual love' (or 'flimsy love', going by the dialogue)!
And I'm now fully convinced Sayo is NOT gonna end up with Mei at the end, cause this is too early and too easy of a way for them to become a real couple. Hell, maybe next chapter Sayo will reveal that her love is possessive, but not necessarily romantic, by turning down Mei.
Whatever happens, I'm still fully #TeamFukatsu, cause her arrow definitely means romantic love. Though if Mei does get turned down by Sayo it's gonna make things harder, cause Mei is gonna turn defensive, since it might be her first rejection.