Love and Faithfulness

I have a question for you today. Why does Proverbs couple together "love" and "faithfulness"?

There are several occasions in which Proverbs simultaneously extols the virtues of love and faithfulness together. "Many a man claims to have unfailing love, but a faithful man who can find?" (20:3). "Love and faithfulness keep a king safe" (20:28a). We also see these two virtues coupled together in 3:3, 14:22; 16:6. The Psalmist continually praises God for demonstrating these two qualities (Psalm 25:10, 40:10, 61:7, 85:10, 86:15, 89:1, 14, 28, 115:1, 138:2, 145:13). See also Ex. 34:6; Is. 55:3; 1 Thess. 3:6; 2 Tim. 1:13-18;; Col. 1:5).