The phrase "deep regret" means feeling very sorry or sad about something that happened or something that was done.
Sentences with «deep regret»
Many will remember with deep regret the opportunities they had to prepare for death while on earth, but did not take advantage of them. (religion.blogs.cnn.com)
When I'm on TV or featured in the media, there is great pride but also a sense of deep regret for not being able to provide for more when I was younger. (gse.harvard.edu)
One way of professionally showing one's deepest regrets for leaving a company is through writing resignation letters. (template.net)