Jesus places a love like the love of God the Father for God the Son within us. He does this by making the Father known to us through His teaching and preaching. Somehow getting to know God awakens love for other people in our hearts. I suppose that makes sense, when we see how much God overlooks in our own lives as He loves us, it motivates us to overlook the offenses of others and love them. In addition, a great impediment to loving one another is the fear that we will not be loved in return. (whether romantically or in friendship) So knowing the God of the universe who knows us completely loves us fully can lessen our need for “getting back” the love we give.
Nevertheless, in my own experience I still crave the approval of others and knowing they care about me despite my assurances of the eternal love of God. I still sometimes fail to reach out in love toward others because I fear they will not respond favorably. Knowing God loves me seems to help my insecurities in this area, but by no means erases them. Part of that is surely the natural result of needing to mature further in my faith. But I think part of it is that God’s love is perceived more and more fully the more we study and learn about and think about Him. So it is easy to forget His love when we get busy or tragedy intrudes. Then, disconnected from feeling the love of God in our lives, we lose some part of the assurance and confidence that comes from knowing Him and revert to a self centered, self seeking love.