Tā yǐ jídà de rèchén tóurù dào zhìyuàn fúwù zhōng.
He threw himself into volunteer service with great zeal.
Tips
usage
热忱 and 热情 both mean enthusiasm, but 热忱 has a warmer, more sincere connotation - a deep-felt passion - while 热情 can apply to more surface-level warmth. 热忱 is more literary and formal in register.
