In formal situations, to respectfully ask for someone’s last name, you can add 贵 before 姓 .
您贵姓？
Nín guìxìng?
(What is) your honorable last name?
For a polite response, you can add 免贵 (miǎnguì, no need for the 'honorable') before your answer!
免贵 ，我姓王。
Miǎnguì, wǒ xìng Wáng.
No need for the 'honorable'. My last name is Wang.
There are different ways to use 辛苦 (xīnkǔ, hard; suffering). Check it out!
辛苦你了！
Xīnkǔ nǐ le!
Thanks for your hard work!
Literal: You suffered for it!
他的工作很辛苦。
Tā de gōngzuò hěn xīnkǔ.
His job is hard.
我知道你很辛苦。
Wǒ zhīdào nǐ hěn xīnkǔ.
I know you are suffering.