IPA: /hɑːrtˈbreɪkɪŋli/
KK: /hɑrtˈbreɪkɪŋli/
In a way that causes great sadness or emotional pain.
The movie ended heartbreakingly, leaving the audience in tears.
Heartbreakingly → It is formed from "heart" (from Old English "heorte", meaning the organ that pumps blood and also symbolizes emotion) and "break" (from Old English "brecan", meaning to shatter or destroy) combined with the adverbial suffix "-ly" (meaning in a manner of). The word "heartbreakingly" describes something done in a manner that causes deep emotional pain or sorrow.
Think of the heart as the center of emotions, and when something 'breaks' it, it causes deep sadness. So, 'heartbreakingly' means something that causes sorrow in an emotional way.
No commonly confused words.