我们高兴地从您的来信中得知……
We are happy to learn from your letter that...
From your letter we have learned that...
我们很遗憾地从您的信中得知……
We regret to learn from your letter that...
We are really sorry to learn from your letter that...
我们为我们的差错向您表示真诚的歉意。
We would like to offer our sincere apologies for the mistake. *“从内心发出的歉意”,用sincere apologies表示。
得知……真是太好了。
It is nice to know that...
It is nice to learn that...
It is nice to hear that...
为……我们很遗憾。
It is regretted that...
It is regrettable that...