苦笑那伤那么微不足道
[kŭ xiào nèi shāng nèi me wēi bù zú dào]
'Bitter laughter shows that wound was so insignificant.' In the Chinese language and context, this conveys the feeling of someone who suffers pain (either physical or psychological) but pretends it is not serious in front of others, trying hard to smile to mask the true feelings.