Here "the heart" represents the feelings or emotions of a person. AT: "make a person feel joyful" or "make a person glad" (See: [[rc://en/ta/man/translate/figs-metonymy]])
# the sweetness of a friend comes from his sincere counsel
Possible meanings are 1) "sweetness" represents kindness. AT: "we recognize our friend's kindness by his counsel" or 2) "sweetness" represents what we appreciate about a person. AT: "what we appreciate about a friend is his advice" (See: [[rc://en/ta/man/translate/figs-metaphor]])