For me this proverb comes to mean, that friendship relies on the fact you tell the truth. Even, when it is painful to hear. And an argument that is based on honesty can often bloom into a true friendship.

从一个打击，交流，友谊的增长
cóng yī ge dǎjī, jiāoliú, yǒuyìde zēngzhǎng
From an exchange of blows, friendship grows