你的无所谓深深的刺痛我心
[nĭ de wú suŏ wèi shēn shēn de cì tòng wŏ xīn]
The phrase describes someone's indifferent attitude hurting another deeply. If there were sincere cares or intense affections between parties, any disregard or nonchalant reaction would hurt sensitivities and cause emotional wounds.