爱莫能助 ài mò néng zhù

爱莫能助 ài mò néng zhù

解释：想要帮忙却没有能力。

Explanation:
I wish I could do so to do you a favour. It expresses the speaker’s willingness to do so, while fails due to some objective reason.

Dialogue:
A：jīntiān xiàwǔ nǐ néng bāng wǒ xiūlǐ yīxià diànnǎo ma?
A：今天 下午 你 能 帮 我 修理 一下 电脑 吗？Can you help me fix my computer this afternoon?
B：duìbùqǐ, shízài ài mò néng zhù, wǒ yào chūchāi qù le.
B：对不起， 实在 爱 莫 能 助， 我 要 出差 去 了。So sorry. I really wish I could, but I am about on business soon.