Actually, Jian Dan only discovered this subsequently.
Perhaps it was because Zhong Tianhao was her first boyfriend, so she was ignorant about many things.
At that time, she thought that she liked him. But they just got on well, that's all.
Now that she thought about it… Although she was very happy when she and Zhong Tianhao were together, the feeling was more like that of chums.
She only realized that after she got together with Chu Liyuan. The feeling of being together with Chu Liyuan was completely different from the feeling of being with Zhong Tianhao.
When she was with Zhong Tianhao, she was very happy. They would fool around, talk, and help each other.
However, when she was with Chu Liyuan, her heart would beat like a jackhammer, her face would blush, and she would have difficulty breathing. Her body temperature would rise, and she would even look forward to all physical contact with Chu Liyuan.