seal of approval

a statement or action that shows a good opinion of something We can finalize the trip to China once we get Bernard's seal of approval. With the seal of approval of a government grant, arts organizations find it easier to raise funds.

An endorsement of something or someone, as in Our candidate doesn't have the governor's seal of approval, or The new management gave the old refund policy their seal of approval. This idiom was used, and perhaps invented, as an advertising gimmick of Good Housekeeping Magazine, which gave its so-called "seal of approval" to products it endorsed; the products' packaging in turn bore a small emblem attesting to this endorsement. The noun seal here is used in the same sense as in set one's seal on.