Why is everyone criticizing Yae? She honestly did nothing wrong. So what if she thought this whole time that Valentines is really special? Honestly there's nothing wrong with that. She sees other giving chocolate? What happened if she thought that they wanted to spend the rest of their life together? In Japan, Valentines is usually giving someone who you have a romantic interest in so it's not that far-fetched.
And come on, she's only in middle school, she has every right to be naive still, give her a break. She's still young and didn't necessarily hit the height of her puberty yet. If you don't like her character, then I don't know what to say other than dropping it or something since she's the main character.
Also spoilers she's not going to put miso and chocolate together ^^;;;
And this miso sounds.. interesting, It looks like something even I could try