This is the 7232nd most frequent Chinese word.
红心
"Red heart," symbolizing sincerity, loyalty, or a literal red-colored heart.
Here, '红心' is used to describe a type of apple that has a red core.
我买了一个红心苹果，味道非常甜美。
I bought a red-heart apple, and it tastes very sweet.
In this context, '红心' metaphorically represents a 'sincere and passionate heart'.
他有一颗红心，为这个项目贡献了很多。
He has a sincere heart, and he contributed greatly to this project.
Here, '红心' refers to the heart shape on playing cards, a common representation of love and affection.