Verses with the word sweetness in the Old Testament (5 verses):

Judges 9:11
But the fig tree said unto them, Should I forsake my sweetness, and my good fruit, and go to be promoted over the trees?

Judges 14:14
And he said unto them, Out of the eater came forth meat, and out of the strong came forth sweetness. And they could not in three days expound the riddle.

Proverbs 16:21
The wise in heart shall be called prudent: and the sweetness of the lips increaseth learning.

Proverbs 27:9
Ointment and perfume rejoice the heart: so doth the sweetness of a man's friend by hearty counsel.

Ezekiel 3:3
And he said unto me, Son of man, cause thy belly to eat, and fill thy bowels with this roll that I give thee. Then did I eat it; and it was in my mouth as honey for sweetness.