Student or Learner
A: Well, I won't answer questions about my sex life. Forget about that.
B: For shame. I thought you'd be honest about everything...
Can "For shame" have the meaning of "what a shame" or "it's a regret" here?
No, and I don't like its use in the original context.
'For shame!' means
(Dictionary.com)You should feel ashamed!:
What a thing to say to your mother! For shame!