It hurts. Right in the kokoro. I applaud Yuu for her efforts during her college days, it's not easy flying to places just to meet your beloved. The only thing I don't like was that she was not too honest, and she regretted not saying anything. That's youth though, the more immature you are, the more scared you are in voicing your inner thoughts. Afraid of getting embarrassed. If she was honest, Miss Sunflower would have probably have lots of happy moments before she die, not just reading novels. And Yuu would have amazing memories to look back, memories of giving your all. I really hate regrets