Should you buy a travel combo that is twice as cheap as a single ticket?

A travel agent offered me a combo of 2.9 million VND per person including round-trip airfare from Hanoi to Nha Trang and two nights at a 4-star hotel (with breakfast and other services). However, when I checked the airfare and hotel separately, I didn't see such a cheap price, even twice as expensive. The combo is valid in July.

Can this combo be trusted? Readers please advise.

Thanks.

Dinh Ha