Realization of Truth; the ‘Gyana’, and constant commitment to it brings stability and constant happiness.
Those who remember and stay with the ‘Truth’ at every moment, and constantly experience it - think and act wisely according to the Gyana – do not have fluctuations and instabilities in their mind. Their mind is always calm and peaceful. Not only they enjoy the bliss and constant happiness themselves, they spread it around as well; to everyone they come in contact with.
On the other hand, those, who have the Gyana - who might know the Truth, but do not really experience it - may not be able to retain constant happiness. They might take on falsehood to impress others, and make false claims to prove and defend themselves, but it does not last for long.
Not just the Gyana (the knowledge) but constant commitment for truth brings constant happiness. For those, who are constantly with the Truth, there are no fluctuations in their mind, nor any variations in their happiness and contentment.
“Just like a lamp in a covered sheltered place does not flicker,
Similar is the simile of a yogi practicing yoga (Union with Almighty) with undisturbed controlled mind.”
||Bhagvad Gita 6:19 ||
Those who are committed to live by the Truth, can neither be influenced by others, nor by the adverse situations they are faced with. Their mind is always focused on the ‘Truth and Truthful Living’.