左耳是说甜言
[zuŏ ĕr shì shuō tián yán]
Words into the Left Ear implies sweet words (praises, flatteries, love confessions) are just heard into one's left ear - metaphorically speaking, one would only listen to kind and gentle words and possibly ignore other voices. Or it can express a wish from someone hoping others only tell her sweet nothings instead of negative criticisms.