If you don't travel now, you might 'live to regret it'. [=you might feel sorry or disappointed about it in the future]
We 'regret' to inform you [=we are sorry to tell you] that we have offered the job to someone else.
It is to be 'regretted' [=it is regrettable/unfortunate] that the program has lost its funding.
(..) I have done many things, Khaleesi, that a righteous man would condemn. And here I am, with no regrets. Bar the gates. Ring the bells. Slowly, Khaleesi. Where are my dragons?! == sync, corrected by == (..)2012 TvShow: Game of Thrones Title: The Old Gods and the New Season: 2 Episode 6