Faithful are the wounds of a friend, but the kisses of an enemy are deceitful.
The clauses' structures are inversions of each other: [adjective][implied copulative verb][noun + prepositional phrase] in the first but [noun + prepositional phrase][implied copulative verb][adjective] in the second. This inversion highlights the opposites "faithful" and "deceitful," "wounds" and "kisses," and "friend" and "enemy."
None of the other translations I referenced have this structure, though, and some even differ in meaning, which I can't account for. My German translation of Proverbs and the Latin Vulgate have the same basic meaning as the NKJV, but the ESV and NIV go in an-other direction. In the ESV, this verse is: "Faithful are the wounds of a friend; profuse are the kisses of an enemy," and in the NIV: "Wounds from a friend can be trusted, but an enemy multiplies kisses."
