The meaning of the verses is as follows. Because they are filled with the presence of Kṛṣṇa, these bhāvas are filled with spiritual happiness. And because even viṣāda and other sorrowful emotions are related to Kṛṣṇa, they should be said to be filled with happiness. The appearance of bhāvas which involve sorrow arise through thinking that one will not attain Kṛṣṇa. However, the cause of that sorrow is a previous experience of Kṛṣṇa. It is certain that the devotees’ aspiration will be fulfilled and they will attain Him. After attaining the Lord, in order to remove selfish thoughts that the Lord belongs to oneself, which may spring from that attainment, and in order to nourish the joy of attaining the Lord, viṣāda and other sorrowful emotions, appear as part of that bliss, just as hunger nourishes enjoyment of food. Such emotions have the appearance of sorrow, but are not really sorrow. This state of happiness and sorrow in the devotee appears like happiness and distress which arise from the material guṇas in the non-devotee. However, this state of happiness and sorrow is not the same. Bhāgavatam says: kaivalyaṁ sāttvikaṁ jñānaṁ rajo vaikalpikaṁ ca yat prākṛtaṁ tāmasaṁ jñānaṁ man-niṣṭhaṁ nirguṇaṁ smṛtam Absolute knowledge is in the mode of goodness, knowledge based on duality is in the mode of passion, and foolish, materialistic knowledge is in the mode of ignorance. Knowledge based upon Me, however, is understood to be transcendental. SB 11.25.24