There are many stages leading to the manifestation of prema.
Among them, those which are most famous in the scriptures will be described here.
The bhagavad-vimukha-jiva, or one whose face is averted from Bhagavan (the Lord),
has from a time without beginning fallen into the unlimited flow of the insurmountable ocean of material existence
and is thus wandering here and there.
When by the special mercy of Bhagavan the jiva’s material existence begins to wane,
he obtains the association of the Lord’s devotees.

At that time, in the company of sadhus (holly persons), he obtains the extraordinary
fortune of hearing from the mouths of elevated devotees the scriptures that are filled
with the glories concerning the three topics: bhaktas, bhakti and Bhagavan.

adau sraddha tatah sadhu sango ’tha bhajana-kriya
tato ’nartha-nivrittih syat tato nistha rucis tatah
athasaktis tato bhavas tatah premabhyudancati
sadhakanam ayam premnah pradurbhave bhavet krama˙ BRS 1:1:11

In the beginning there is transcendental faith -adau sraddha-
threafter (the stage of) association with the saints - tatah sadhu sango-
threafter (the external and internal ) cleaning activity of worshiping (of the Lord)-bhajana-kriya-
thereafter therebe (the stage) of removed unwanted attachments -tato ’nartha-nivrittih syat

thereafter (the stage of) steadiness -tato nistha (by which one's bhajan is not anymore disturbed by anarthas)
threafter taste (in bhajan and the spiritual objects of worship- Radha-Krishna -rucis tatah
and certainly spiritual attachment (for the Lord and His associates) -athasaktis

thereafter (the stage of) beginning of spiritual love -tato bhavas
thereafter the divine love appears -tatah premabhyudancati

This would be - bhavet- the sequence -krama- by which this divine love -ayam premnah
appears in the practicing devotee -pradurbhave sadhakanam.

This scriptural description of the evolution of prem is actually a description
of the development of the devotee's uncompromising desire for the Lord.
The beginning of wanting the Lord is divine faith ( sraddha) which gradually develops into prem.
That desire appears as the rising sun of prem.

Just as the rising sun reveals the world around us,
so the rising sun of love for Krsna reveals Him.