IPA: /ˈhɑrtˌfɛlt/
KK: /hɑrtˈfɛlt/
Sincerely and deeply felt; showing genuine emotion or care.
She wrote a heartfelt letter to her friend who was going through a tough time.
Heartfelt → It is formed from "heart" (from Old English "heorte", meaning the organ that pumps blood and also symbolizes emotion) and "-felt" (from Old English "fealtan", meaning to feel). The word "heartfelt" means deeply felt or sincere, coming from the heart.
Think of the heart as the center of emotions and feelings, and remember that heartfelt means something that is deeply felt or sincere.
No commonly confused words.