Attraction and affection

Love is attraction in the beginning.
Attraction is triggered by the qualities that the object of love possesses.

These main attractive qualities are

Belongingness
Beauty (Śrī)
wealth
power
Knowledge,
fame and
Renunciation - the quality of renouncing one's own pleasure in order to make the lover happy.

All these opulences are perfectly situated in the Transcendental Lord Șri Krișna,
but because Krishna cannot be perceived by the material senses, this attraction
is triggered only by practicing spiritual devotion, known as sadhana-bhakti or bhakti-yoga
and becomes affection and ultimately love.

In this context, Sri Caitanya, a form of Krishna, said:

sādhana-bhakti haite haya 'rati'ra udaya
rati gāḍha haile tāra 'prema' nāma kaya

Through devotional practice one develops affection (for Krișna) -haite sādhana-bhakti haya ratira
and (when) this affection intensifies, it is called spiritual love. - gāḍha haile tāra rati kaya nāma prema