“youths.” The Hebrew is literally “sons,” but the reading, “I saw among the sons” is awkward in English.
“sense.” The Hebrew word is leb (#03820 לֵב), which is often translated “heart,” but this is one of those cases where that translation would cause confusion. In modern English, the word “heart” usually refers to emotion or passion, but that is not its meaning here. The function of the brain was unknown in biblical times, so things that we generally assign to the brain, like thinking, attitudes, understanding, and good sense, were assigned to the heart. In this case, the young man lacked “good sense.”
[For more on the Hebrew word leb and “heart,” see commentary on Prov. 15:21, “sense.”]