少小无猜

Explanation: Guess: suspicion. That when young men and women to play with the innocent, not Bi Xianyi. 　　Source: Tang Li Bai, "Ezra," a long poem of dry years cohabitation, two small non-suspect guess. " 　　Examples: Both of us this is a ~, while pretending to look like the bride and groom indeed still do not know what relationship the bride and groom. (Chiang "Yalu River")