nǐ / xiàn / zài / cái / dào / qiàn / yǐ / jīng / wǎng / fèi / wǒ / zhī / qián / de / yì / fān / kǔ / xīn / le

你现在才道歉，已经枉费我之前的一番苦心了。

Apologizing only now has made all my previous efforts pointless.