en_tn/pro/25/03.md

Like the heavens are for height and the earth is for depth, so the heart of kings is unsearchable

The hearts of kings are compared to the size of the heavens and the earth. Alternate translation: "Just as no one can measure the height of the heavens or the depth of the earth, even so no one can understand the heart of kings" (See: rc://en/ta/man/jit/figs-simile)

heavens

This refers to everything we see above the earth, including the sun, moon, and stars.