"He who owns the inner square of the house is the master of the outer."
Owning the "inner square" of yourself (being confident and feeling good with your self) will show on the outside

"Peace is the father of friendship."

"A sharp word is as tough as a bow-string. A sharp word cannot be cured, but a wound may."

And two more that i hope someone will explain in a good way:
"The stream may dry up, but the watercourse still keeps its name."

"When water is poured on the head it finds its way down to the feet."

And a bonus for utamaroho:
"If you are not able to build a house at once, you first build a shed."
..."Do your best." ;)