CC Ādi 4.140

yadyapi nirmala rādhāra sat-prema-darpaṇa
tathāpi svacchatā tāra bāḍhe kṣaṇe kṣaṇa
Word for word: 
yadyapi — although; nirmala — pure; rādhāra — of Śrīmatī Rādhārāṇī; sat-prema — of real love; darpaṇa — the mirror; tathāpi — still; svacchatā — transparency; tāra — of that; bāḍhe — increases; kṣaṇe kṣaṇa — every moment.
Translation: 
“Although Rādhā’s love is pure like a mirror, its purity increases at every moment.