The desire for happiness is a proof of the ever existing happiness of the Self.

Ramana Maharishi: The desire for happiness (sukha prema) is a proof of the ever existing happiness of the Self. Otherwise how can desire for it arise in you? If headache was natural to human beings no one would try to get rid of it. But everyone that has a headache tries to get rid of it, because he has known a time when he had no headache. He desires only that which is natural to him. So too he desires happiness because happiness is natural to him. Being natural, it is not acquired. Man’s attempts can only be to get rid of misery. If that be done the ever-present bliss is felt. The primal bliss is obscured by the non-self which is synonymous with non-bliss or misery. Duhkha nasam = sukha prapti. (Loss of unhappiness amounts to gain of happiness.) Happiness mixed with misery is only misery. When misery is eliminated then the ever-present bliss is said to be gained. Pleasure
which ends in pain is misery. Man wants to eschew such pleasure. Pleasures are priya, moda and pra-moda. When a desired object is near at hand there arises priya: when it is taken possession of moda arises; when it is being enjoyed pra-moda prevails. The reason for the pleasureableness of these states is that one thought excludes all others, and then this single thought also merges into the Self. These states are enjoyed in the Anandamaya kosa only. As a rule Vijnanamaya kosa prevails on waking. In deep sleep all thoughts disappear and the state of obscuration is one of bliss; there the prevailing body is the Anandamaya. These are sheaths and not the core, which is interior to all these. It lies beyond waking, dream and deep sleep. That is the Reality and consists of true bliss (nijananda).