I'm sorry I can't stay with you, time's really tight.

对不起，我不能在这儿陪你，我赶时间。

youdao

I'm sorry but I can't stay any longer.

很抱歉，我不能再待下去了。

《牛津词典》

Just ten more minutes. Then I have to go. I'm sorry, but I can't stay.

只能再十分钟。然后我就必须走了。很抱歉，我不能留下来。

youdao