be sorry
regret
be sorryRegret and be sorry are both used to say that someone feels sadness or disappointment about something that has happened, or about something they have done. Regret is more formal than be sorry.
You can say that you regret something or are sorry about it.
You can also say that you regret or are sorry that something has happened.
You can also say that you regret doing something.
Be Careful!
Don't say that you 'are sorry doing' something.
When you are apologizing to someone for something that has happened, you can say that you are sorry about it.
You can also report someone's apology by saying that they are sorry about something.
Be Careful!
Don't say that you are 'sorry for' something.
In conversation, don't apologize by saying that you 'regret' something. Regret is only used in formal letters and announcements.
When you are giving someone some bad news, you can begin by saying 'I'm sorry to tell you...'. In a formal letter, you say 'I regret to inform you...'.