Happiness of transcendental quality is called brahma-saukhyam, which will be clearly described in the Fifth Canto
SB Canto 2
What is realized as the Absolute Brahman is full of unlimited bliss without grief. That is certainly the ultimate phase of the supreme enjoyer, the Personality of Godhead. He is eternally void of all disturbances and fearless. He is complete consciousness as opposed to matter. Uncontaminated and without distinctions, He is the principle primeval cause of all causes and effects, in whom there is no sacrifice for fruitive activities and in whom the illusory energy does not stand.
The supreme enjoyer, the Personality of Godhead, is the Supreme Brahman or the summum bonum because of His being the supreme cause of all causes. The conception of impersonal Brahman realization is the first step, due to His distinction from the illusory conception of material existence. In other words, impersonal Brahman is a feature of the Absolute distinct from the material variegatedness, just as light is a conception distinct from its counterpart, darkness. But the light has its variegatedness, which is seen by those who further advance in the light, and thus the ultimate realization of Brahman is the source of the Brahman light, the Supreme Personality of Godhead, the summum bonum or the ultimate source of everything. Therefore, meeting the Personality of Godhead includes the realization of the impersonal Brahman as realized at first in contrast with material inebriety. The Personality of Godhead is the third step of Brahman realization. As explained in the First Canto, one must understand all three features of the Absolute—Brahman, Paramātmā and Bhagavān.
Pratibodha-mātram is just the opposite conception of material existence. In matter there are material miseries, and thus in the first realization of Brahman there is the negation of such material inebrieties, and there is a feeling of eternal existence distinct from the pangs of birth and death, disease and old age. That is the primary conception of impersonal Brahman.
The Supreme Lord is the Supreme Soul of everything, and therefore in the supreme conception affection is realized. The conception of affection is due to the relationship of soul to soul. A father is affectionate to his son because there is some relationship of nearness between the son and the father. But that sort of affection in the material world is full of inebriety. When the Personality of Godhead is met, the fullness of affection becomes manifested because of the reality of the affectionate relationship. He is not the object of affection by material tinges of body and mind, but He is the full, naked, uncontaminated object of affection for all living entities because He is the Supersoul, or Paramātmā, within everyone's heart. In the liberated state of affairs, the full-fledged affection for the Lord is awakened.
As such, there is an unlimited flow of everlasting happiness, without the fear of its being broken as we have experienced here in the material world. The relationship with the Lord is never broken; thus there is no grief and no fear. Such happiness is inexplicable by words, and there can be no attempt to generate such happiness by fruitive activities by arrangements and sacrifices. But we must also know that happiness, unbroken happiness exchanged with the Supreme Person, the Personality of Godhead as described in this verse, transcends the impersonal conception of the Upaniṣads. In the Upaniṣads the description is more or less negation of the material conception of things, but this is not denial of the transcendental senses of the Supreme Lord. Herein also the same is affirmed in the statement that the Supreme Lord is pure (suddham). The word suddham indicates that the senses of the Personality of Godhead are not made of the material elements; they are all transcendental, free from all contamination of material identification. And also the liberated souls are not devoid of senses; otherwise there cannot be any reciprocation of unhampered spiritual happiness exchanged between them in spontaneous unbroken joy. All the senses, both of the Lord and of the devotees, are without material contamination. They are so because they are beyond the material cause and effects, as clearly mentioned herein (sad-asataḥ param). The illusory, material energy cannot work there, being ashamed before the Lord and His transcendental devotees. In the material world the sense activities are not without grief, but here it is clearly said that the senses of the Lord and the devotees are without any grief. There is a distinct difference between the material and spiritual senses. And one should understand it without denying the spiritual senses because of a material conception.
The senses in the material world are surcharged with material ignorance. In every way, the authorities have recommended purification of the senses from the material conception. In the material world the senses are manipulated for individual and personal satisfaction, whereas in the spiritual world the senses are properly used for the purpose for which they were originally meant, namely the satisfaction of the Supreme Lord. Such sensual activities are natural, and therefore sense gratification there is uninterrupted and unbroken by material contamination because the senses are spiritually purified. And such satisfaction of the senses is equally shared by the transcendental reciprocators. Since the activities are unlimited and constantly increasing, there is no scope for material attempts or artificial arrangements. Such happiness of transcendental quality is called brahma-saukhyam, which will be clearly described in the Fifth Canto.