Mangaka aren't hiding their intentions anymore apparently. The title says: the mc with the light hair won't get sad.
the love interest is a dark-haired tall responsible girl, so she's guaranteed to have a totally ludicrous melancholy backstory and the story is guaranteed to dwell on her being unable to deal with anything that is not academic and the mc being perfect in everything that is important in life while the love interest fails at all that and is a melancholy damsel in distress.
Here we go: deciding that a person you barely know is a certain way and contradicting them when they say you are wrong. Typical.
Right. She won't get it right away, because she isn't as insightful into other people she just met as you are.