This is the 596th most frequent Russian word.
сердца
"Serdtsa" means "hearts" in English.
Here, 'сердца' is used in a figurative sense to denote sincerity and deep feeling.
Он говорил это от всего сердца.
He said it with all his heart.
In this sentence, 'сердца' refers to the physical shape of a heart.
В центре города стоит памятник в форме сердца.
In the city center, there is a monument in the shape of a heart.
Here, 'сердца' refers to the beating of a human heart as a vital organ.