There are 4 elements that establish True Love. They are Loving kindness, Compassion, Joy and Equanimity. They are also known as the 4 Immeasurables.

Compassion is the capacity to transform sufferings. We need to first understand the nature of our sufferings before we can transform them. If we know how to help ourselves suffer less, it will be easier for us to help others do the same.
Joy is about knowing how to bring joy to ourselves and others. It can be experienced in every moment of our lives if we know how to nourish ourselves with feelings of peace and happiness. When we master this, we will be able to help others do likewise.
Equanimity is about non-discrimination, non-separation and inclusiveness. We recognize that the happiness, joy and sufferings of others are our happiness, joy and sufferings, and vice versa. We and others are no longer separate entities. We "inter-are".
Source: Teachings by Thay at Plum Village in Jul 2009