From Chibi Manga:

After being broken-hearted 3 times, in Kozue's mind, she no longer needed men anymore. But she unconsciously started to care about this mature and considerate Asano-sensei. After knowing Asano-sensei cherished and loved his girlfriend so much, she then discovered that she fell deeply in love with Asano-sensei...

Even though being rejected by the teacher, But Kozue still couldn't forget her love and the romance for the teacher......!?