lòng thành thực 
sincerity [ lòng ] : heart, spirit, feeling(s), innards, bowels, intestines
[ thành ] : (1) citadel, fortress, wall; (2) to, into; (3) to succeed; (4) to become; (5) honest, sincere
[ thực ] : to grow, develop, reproduce, colonize; to eat (up); (2) true, real
Most Common Compounds Set 1:
Most Common Compounds Set 2 :