không phải là chuyện dễ 
not an easy thing to do [ không ] : (1) no, not; (question tag); (2) air; (3) empty
[ phải ] : (1) correct, right (opposite of left), right (opposite of wrong); (2) must, have to
[ là ] : that; to be
[ chuyện ] : story, conversation, situation, issue, matter; to talk, converse, communicate
[ dễ ] : easy, likely
Most Common Compounds Set 1:
Most Common Compounds Set 2 :