This is the 8902nd most frequent Polish word.
serca
The Polish word "serca" means "hearts" (plural) or "of the heart" (genitive singular).
Here, 'serca' is a genitive singular form of the noun 'serce,' used to express possession or association with 'my heart.'
Mam wiele miłości w moim sercu.
I have much love in my heart.
In this sentence, 'serca' is used as the accusative plural form of 'serce,' meaning 'hearts' and indicating the direct object of the action performed in the context.
Zdobyłem serca słuchaczy swoją przemową.
I won the hearts of the listeners with my speech.
'Serca' here is part of a proper noun, possibly in a genitive case usage related to naming conventions where it signifies 'of the heart'.