Tell me if you haven't heard of the flower name.

It means it's hard to be flat. The past that I can't go back to, the fetters that I can't let go, have all changed. According to relevant information, it is a metaphor to meet the right person, but miss her best opportunity. This sentence comes from the Japanese anime "I don't know the name of the flower", also known as "We don't know the name of the flower we saw that day". There is no if in life, friendship needs to be done and cherished. This is also the theme of this animation.