4 sentences

1. 为了这件事，他没少费心。

   wèi​le zhè jiàn shì, tā méi shǎo fèi​xīn.

   He took a lot of trouble over this matter.

   Source: Dong Chinese Dictionary

2. 这件事还要多费心请您帮忙。

   zhè jiàn shì hái yào duō fèi​xīn qǐng nín bāng​máng.

   I'll have to trouble you to help me with this matter.

   Source: Dong Chinese Dictionary

3. 为了照顾生病的老人，他真是费心了。

   wèi​le zhào​gu shēng​bìng de lǎo​rén, tā zhēn shì fèi​xīn le.

   He really put in a lot of effort to take care of the sick elderly person.

   Source: Dong Chinese Dictionary

4. 劳您费心了。

   láo nín fèi​xīn le.

   Thank you for your trouble.

   Source: Dong Chinese Dictionary