What does the phrase 'As water reflects the face, so the heart reflects a person' mean?

Greetings and blessing,

King Solomon, the wise, said about man: "As water reflects the face, so the heart reflects a person" (Proverbs 27). The Metzudat David commentary explains: "Just as water shows the image of the face looking into it, if the water is clear it reflects clearly; likewise, the heart of a person reflects towards another person - if his heart is good toward his friend, his heart will also be good; if it is evil, it will also be evil."

This is a principle in the world of Hashem, which naturally applies also to non-Jews.

With blessing,

Daniel Bales