A friend is easier lost than found
得朋友难，失朋友易。

A friend in need is a friend indeed.
患难见真情。

A friend is never known till a man has need.
需要之时方知友。

A friend without faults will never be found.
没有十全十美的朋友。

Between friends all is common.
朋友之间不分彼此。

He is a good friend that speaks well of us behind our backs.
背后说好话，才是真朋友。

Life without a friend is death.
没有朋友，虽生犹死。

Misfortune tests the sincerity of friends.
患难见真情。