Without accepting diksa from a bona fide guru, can one develop bhakti or not? Some think that chanting, remembering, reading books, and performing arcana, sravanam and kirtanam is sufficient and there is no need for a mediator. They think that accepting a 'ritvik' person is sufficient for attaining pure bhakti, and there is no need of accepting diksa from any living self-realized guru...

If one's guru is not qualified, then, taking his permission, the disciple should at once take initiation from a higher rank of guru. This is not an offense. If that guru is not giving permission, he should at once be given up and the disciple should take proper initiation. This is because that guru is not a Vaisnava...

[Question:] Since we spirit souls haven't fallen from Krsna's pastimes in Goloka Vrndavana, why do the scriptures say we ‘revive' our relationship with Krsna, or that we have ‘forgotten' that relationship? Since we have never experienced it, what is the question of ‘reviving' or ‘forgetting' it?

You should understand who is a real guru. He is the abode of bhakti, and he has all kinds of serving moods towards Radha-Krishna Conjugal or Mahaprabhu. He can give sadhana-bhakti, and he can also give rati - a high class of rati. If he is qualified to even give prema-bhakti in Goloka Vrindavana, and the love and affection of Conjugal Radha-Krishna, can he fall down?