kako da ne

1. (in reply to a request) of course; certainly; sure
   — Možete li mi pomoći? — Kako da ne, izvolite. — “Could you help me?” “Of course, go ahead.”
2. ironic (as a reply) yeah, right; as if
   — Vratiću ti pare sutra. — Kako da ne! — “I'll pay you back tomorrow.” “Yeah, right!”

The meaning depends on intonation: polite agreement or mocking disbelief.