Wisteria Falls in its own words, why does the author's anxiety and sadness no longer exist, only the peace of mind and the joy of life?

Ten years of catastrophe brought great suffering to the author's family, even the wisteria outside the house suffered. Now the younger brother who loves her deeply is terminally ill, and the author is in a heavy mood. It was when she was in a heavy heart that the author "stopped" before the flower. "I have never seen a vine in full bloom like this" and "I can't help but stop" show the author's feelings of being attracted and moved by flowers. Wisteria has also suffered with the changes of the world, but after the suffering, it immediately recovered its vitality, "laughing" and "roaring" and "I have blossomed!" It shows the happiness of flowers' life. This kind of joy infected the author, "taking away the anxiety and sadness that have been pressing on my mind for years", freeing the author from the thoughts of "life and death" and the sadness of "hands and feet", feeling "spiritual peace and joy of life" and realizing the truth that "flowers and people will encounter all kinds of misfortunes, but the long river of life is endless".