⇒ 帮我打扫房间,真难为你了。 (Bāng wǒ dǎsǎo fángjiān, zhēn nánwei nǐ le.) Thank you for helping me with the cleaning — I know I've really put you out.
(指做难事) be tough
⇒ 一个人把几个孩子拉扯大,真难为她了。 (Yī gè rén bǎ jǐ gè háizi lāchě dà, zhēn nánwei tā le.) It must have been very tough for her, bringing up all those children on her own.