*Good wine needs no bush*
We see shopkeepers decorate their shops for advertisements.
In this modern world, advertisement *plays* an important role in business.
But we can see certain goods *are sold* in the market without any advertisement.
This *shows* that goods *are sold* not because of advertisement but because of quality and worthiness.
In olden days it was customary to keep in wine shops a bush of leaves to show the quality of wine.
Quality goods *are sold* even without any advertisement.
Propaganda or advertisement is neccessary only for worthless stuff.
*Propaganda - விளம்பரம்*
Similarly a great man *is respected* for his own conduct. He needs no propaganda.
Thus the proverb stresses that quality is more important than advertisement. As for a man, his character and manners are more important than any propaganda.