One'll rue the day In english explanation

Once something has been done, you can do nothing but face the consequences.

It is useless regretting about past events that cannot be changed.

Used when one has had time to clearly or objectively think about something that had happened, and they often feel sorry or ashamed about it.

To publicly show one's feeling of sadness, guilt, or anger about something or that one is pretending to do so.

To have to regret, withdraw or feel foolish about what they have said.