Inner feelings unmoved
Not feeling anything towards something that you should have feelings for; utterly unmoved; aloof; indifferent
Negative
None
无动于中 (wú dòng yú zhōng)
This is an HSK chengyu
Though 无动于中 is listed as a variation of this chengyu, the 现代汉语规范词典 (Xiàn Dài Hàn Yǔ Guī Fàn Cí Diǎn Dictionary) instructs its readers to avoid this spelling
《聊斋志异》(Liáo Zhāi Zhì Yì) by Qīng Dynasty (清, 1644 - 1911) author 蒲松龄 (Pú Sōng Líng). The book is a collection of supernatural tales, and its English names include "Strange Tales from the Liaozhai Studio" and "Strange Stories from a Chinese Studio."
This chengyu is from a line in the work listed in the "Origin" section above