bhakti-siddhānta - conclusive decision in devotional service; śāstra - according to the scriptural injunctions; ācāra-nirṇaya - ascertainment of behavior; tomā-dvāre - by you; karāibena - will cause to be done; bujhiluṅ - I can understand; āśaya - His desire.

“I can understand from the words of Śrī Caitanya Mahāprabhu that He wants you to write books about the conclusive decision of devotional service and about the regulative principles ascertained from the revealed scriptures.