Not getting that white skirt filled Xia Ruya's heart with jealousy towards Wen Xinya. She had originally already liked that white skirt very much, wanted it at all costs, and wanted to use it to obtain victory over Wen Xinya once.
However, her plot fell through in front of that Mr. Si!
Perhaps, similarly to Jiang Ruoyin, most people would think that it was just a white skirt and to just let it pass. However, to Xia Ruya, it wasn't simply a dress, it was a battle between her and Wen Xinya.
However, she lost!
To let Wen Xinya embarrass her in public, it was a loss!
To let Wen Xinya take away her beloved item, it was a loss!
To let Wen Xinya snatch the man that she adored, it was a loss!
Within a short exchange, she had lost terribly, got stripped of her pride, and humiliated badly!