Pure Devotion: Characteristics of Pure Devotion

Q. Prabhupada had undergone so many troubles in his life; still he continued his preaching in his life even after having so many temples to manage. That was his success. But when we are trying to follow his teachings in our life, why are we not able follow it perfectly?

Sometimes we say Maya is so strong. What will happen to us? When we are sick, it is so difficult to even complete 16 rounds. Why does this happen to us?

Q. I have a question that is bothering me. I went last year to see MATA AMRITANDAMAYI also known as AMMA. She is a big devotee of Lord Krishna, always speaks of Lord Krishna's glories. She has the same message to humankind that our place is with the Lord and that we have to go back to Lord Krishna. My question is, I have seen devotees of amma chanting "om nama shivaya". So I am confused. What is the difference between the maha mantra and this mantra?

I hope you would enlighten me on this.

Q. What is the exact meaning of pure devotional service? How can we perform this without expectation?

Srila Rupa Goswami gives the definition of pure devotional service in Bhakti Rasamrta Sindhu 1.1.11 (Nectar of devotion) as below:

anyabhilasita-sunyam
jnana-karmady-anavrtam
anukulyena krsnanu-
silanam bhaktir uttama