我肯定是知无不言
“I'll tell you everything I know.”
THE DIALOGUE REEL
作为他的好朋友兼发小
“As his best friend and childhood buddy,”
我 肯定是 知无不言
“I'll tell you everything I know.”
Direct spoken expression in this communicative setting.
A 'faxiao' implies deep, lifelong familiarity, granting the speaker authoritative insider knowledge about the friend.
LEARNING CHUNKS & PARTICLES
tell all one knows without reservation
A classical four-character idiom (chengyu) commonly paired with 言无不尽 to pledge total transparency.