A honeyed tongue with a heart of gall.
More French Proverbs:
Fortune can take from us only what she has given us.French
The first step is all the difficulty.
French
A dog may look at a bishop.
French
The blade wears out the sheath.
French
There never was a banquet so sumptuous but some one dined ill at it.
French
Maturity consists of no longer being taken in by oneself.
French