The last little bit took me a while to read but she seems like the serious type who doesn't want to start something that may not lead anywhere because she's looking for that person she's going to fall for. In this case, it isn't the MC.
For the last bit,
"Because I might fall in love someday"
"Because I might fall in love someday, baby"
I read it as,
The first is what dark hair says. The second (no speech balloon) is what light hair hears/thinks before she replies.
Sometimes realizing your true feelings doesn't lead to love, no matter how good it seems "on paper". The ending feels like light hair accepting the situation with grace instead of holding onto her crush, dark hair doesn't let it get messy and give in to pity/pity sex. A happy ending for a sad story.