CC Madhya 4.195
ihā āsvādite āra nāhi cauṭha-jana
Only Śrī Caitanya Mahāprabhu has tasted the poetry of this verse. No fourth man is capable of understanding it.
This indicates that only Śrīmatī Rādhārāṇī, Mādhavendra Purī and Caitanya Mahāprabhu are capable of understanding the purport of this verse.