This is the 5431st most frequent Polish word.
szczęśliwa
"Happy" (feminine form).
Here, "szczęśliwa" is used as an adjective modifying the subject "I" in the first-person feminine form, expressing a state of happiness.
Jestem szczęśliwa, gdy świeci słońce.
I am happy when the sun is shining.
In this sentence, "szczęśliwa" is again an adjective describing the feminine past tense subject, aligning with the speaker's emotional state.
Kiedy byłam dzieckiem, czułam się szczęśliwa.
When I was a child, I felt happy.
Here, "szczęśliwa" is used as an adjective modifying the noun "wiadomość" (news), describing the nature of the news being pleasing or fortunate.