Vaishnava Samhita. Meera Charitam II. Vol II Book VI Chp 13 Shloka 21

गोपीभावो दुरूहोsयं योगिभिश्च शुकादिभिः |
गोपिका एव जानन्ति गोपीभावं सुनिर्मलम्  ||

It is very difficult even for great yogis like Shri Shuka to understand Gopi prem fully. Only the Gopis know the pious import of true Gopi prem