According to Osho, bhakti-rasa arises when your identity shifts from body and mind to soul. Body-identity yields sex; mind-identity yields love; soul-identity flowers as devotion—the radical transmutation of sexual energy, with no falling back. Love is the bridge from sex to devotion. Nurture love and consciously disidentify from body-mind; with this third recognition—'I am the soul'—the current of devotion begins to flow.
See yourself as the soul (not just body or mind), let love mature, and devotion naturally appears.