This is the 41st most frequent Croatian word.
nam
"Nam" in Croatian means "to us" or "for us."
In this sentence, 'nam' functions as an indirect object (dative case) and means 'to us'.
Donesite nam knjigu, molim vas.
Bring us the book, please.
Here, 'nam' indicates the recipients (dative case) of the honesty, thus meaning 'to us' again.
Važno je da nam uvijek budete iskreni.
It's important that you are always honest with us.
In this case, 'nam' expresses the experiencer of the clarity or understanding, functioning as an indirect object in the dative case.