"dear lady" is correct and usable in written English.
It is used in an informal, polite way to address a woman. For example, "Dear lady, thank you for your help yesterday."
Ridiculous, my dear lady!
But dear lady, I don't blame you.
A dear lady and good friend.
Give her a healthy old age, my dear lady.
"Oh, dear Lady Gaga, thank you for that wonderful tribute," she said, to wild applause.
("Dear Lady MacD: Gotta run. Long story. Best to the kids!
Taking the stage, he said, "Good evening, dear ladies and gentlemen, dear friends, this is a happy day for us".
"My dear ladies," he wrote, "I do not compete for work".
Being a typically fussy masculine critic I naturally feel that while the dear ladies may have made the best of the material they have not made the most of it.
Dear ladies and gentlemen, over the last few years I've often written your leaders, but now that my term is ending I've decided my last letter should be to you, the Arab masses, the Arab street, who have paid such a high price for this ongoing conflict.
Hello dear Ladies and Gentlemen!
