Learn Croatian: Jeste li rekli istinu šefu? - Did you tell the boss the truth?

The word šef (boss) is in the dative case here, making it šefu. We use the dative case for the indirect object, which is the person receiving something or being told something (like telling the truth to the boss). For most masculine nouns, you form the dative by adding -u to the end.

Both istinu and šefu end in -u. Are they both in the dative case?

No! This is a very common trap. istinu is in the accusative case because it is the direct object (the thing being told). It comes from the feminine noun istina (truth), which changes its -a to -u in the accusative. On the other hand, šefu is a masculine noun in the dative case. They just happen to share the same ending here.

Why does the sentence start with Jeste li, which means 'Are you', if the translation is 'Did you'?

This is how the past tense works in Croatian. You form it by combining a helper verb (a form of biti, meaning 'to be') with an action word (the past participle). Here, Jeste li (Are you) pairs with rekli (told) to mean 'Did you tell'.

Why does rekli end in -i?