The only way to develop prema bhakti for Sri Krishna in the beginning is to have very strong determination that I don’t want to take birth again in this material world because I am spirit soul so how will I find permanent happiness here. After continual practice with great determination you will be energised by spiritual energy and then chanting of the holy name of Sri Krishna will become like pure honey and you will want to constantly drink the nectar. These tears will wash away all our impurities due to our material conditioning and give us total bliss but effort is needed in the beginning. Like Bhagavad Gita says what is poison in the beginning will become nectar in the end. In material life what is nectar in the beginning turns out to be poison in the end.