A man must eat a peck of salt with his friend before he knows him
问题描述：
A man must eat a peck of salt with his friend before he knows him
答
在你信任你的朋友之前，先要深入了解你的朋友
答
日久见人心
答
一个人在了解他的朋友之前必须要多和他相处.
或者：一个人必须得和他的朋友相处久了才能了解他.
eat a peck of salt with 与某人相处甚久(深知其人)