The more we obey God, the more we desire to help others. The more we help others, the more we love God and on and on. Conversely, the more we disobey God and the more selfish we are, the less love we feel.
Trying to find lasting love without obeying God is like trying to quench thirst by drinking from an empty cup—you can go through the motions, but the thirst remains. Similarly, trying to find love without helping and sacrificing for others is like trying to live without eating—it is against the laws of nature and cannot succeed. We cannot fake love. It must become part of us. The prophet Mormon explained:
But charity is the pure love of Christ, and it endureth forever; and whoso is found possessed of it at the last day, it shall be well with him.
Wherefore, my beloved brethren, pray unto the Father with all the energy of heart, that ye may be filled with this love, which he hath bestowed upon all who are true followers of his Son, Jesus Christ; that ye may become the sons of God; that when he shall appear we shall be like him, for we shall see him as he is; that we may have this hope; that we may be purified even as he is pure. Amen.
Source: Moroni 7:47-48; The Book of Mormon: Another Testament of Jesus Christ