遗憾用英语怎么说

遗憾 is the Chinese word for "regret" or "disappointment." It comes from the Chinese characters "遗" and "憾," which literally mean "to leave behind" and "displeasure" or "sorrow," respectively.
Here are some English examples sentences using the word "regret":
I regret not taking that opportunity when it was presented to me.
She expressed her regret over the situation and apologized for her mistakes.
He felt a deep sense of regret when he realized what he had done.
We regret to inform you that your application has been denied.
It is with great regret that I must resign from my position.