4 sentences

1. 他是一个非常有责任心的人。

   tā shì yī gè fēi​cháng yǒu zé​rèn​xīn de rén.

   He is a very responsible person.

   Source: Dong Chinese Dictionary

2. 她的责任心呢？

   tā de zé​rèn​xīn ne?

   Where's her sense of responsibility?

   Source: OpenSubtitles

3. 你是全哈佛最有责任心的学生。

   nǐ shì quán Hā​fó zuì yǒu zé​rèn​xīn de xué​sheng.

   You're the most conscientious student at Harvard.

   Source: OpenSubtitles

4. 他在家里排行老大，所以从小就非常有责任心。

   tā zài jiā​lǐ pái​háng lǎo​dà, suǒ​yǐ cóng xiǎo jiù fēi​cháng yǒu zé​rèn​xīn.

   He is the eldest child in his family, so he has been very responsible since he was young.

   Source: Dong Chinese Dictionary