眼見為實，耳聽為虛 [－见为实－－听为虚]

Jyutping ngaan5 gin3 wai4 sat6 , ji5 ting1 wai4 heoi1
Pinyin yǎn jiàn wéi shí , ěr tīng wéi xū

Definitions (CC-CEDICT)
  1. to believe what one sees, not what one hears (idiom). Don't believe what people tell you until you see if for yourself.
  2. It ain't necessarily so.