3 sentences

1. 面对大家的苦苦哀求，他依然无动于衷。

   miàn​duì dà​jiā de kǔ​kǔ āi​qiú, tā yī​rán wú​dòng​yú​zhōng.

   In the face of everyone's desperate pleas, he remained unmoved.

   Source: Dong Chinese Dictionary

2. 那位好姑娘居然对你的魅力无动于衷。

   nà wèi hǎo gū​niang jū​rán duì nǐ de mèi​lì wú​dòng​yú​zhōng.

   That nice young lady seemed somehow impervious to your charms.

   Source: OpenSubtitles

3. 他已经到了刀枪不入的境界，随你怎么骂他都无动于衷。

   tā yǐ​jīng dào le dāo​qiāng​bù​rù de jìng​jiè, suí nǐ zěn​me mà tā dōu wú​dòng​yú​zhōng.

   He has reached a state of being completely thick-skinned; he remains indifferent no matter how you scold him.

   Source: Dong Chinese Dictionary