chân thành cáo lôi 
to sincerely apologize [ chân ] : (1) foot, leg; member; (2) true, sincere, real, honest
[ thành ] : (1) citadel, fortress, wall; (2) to, into; (3) to succeed; (4) to become; (5) honest, sincere
[ cáo ] : (1) to announce, report; to feign, fake; (2) fox
[ lôi ] : (1) thunder; (2) to drag, pull; (3) (explosive) mine
Most Common Compounds Set 1:
Most Common Compounds Set 2 :