This is the 6928th most frequent Chinese word.
热心
Enthusiastic; warm-hearted.
This sentence uses "热心" as an adjective to describe a person's nature as being enthusiastic and willing to assist others.
她是一个非常热心的人，总是帮助别人解决问题。
She is a very enthusiastic person who always helps others solve their problems.
Here, "热心" expresses enthusiasm towards a subject, specifically charitable activities.
他对公益活动非常热心，经常参加各种志愿者服务。
He is very enthusiastic about charitable events and often participates in various volunteer services.
In this instance, "热心" is used as an adjective to highlight the quality of volunteers who are eager and willing to contribute.