all very well for somebody to do something

Từ điển Oxford Advanced Learner 8th

ˌall very ˈwell (for sb) (to do sth) idiom
(informal)used to criticize or reject a remark that sb has made, especially when they were trying to make you feel happier about sth
•It's all very well for you to say it doesn't matter, but I've put a lot of work into this and I want it to be a success.
Main entry: ↑well_idiom