IPA: /ˈhær.oʊ.ɪŋ.li/
KK: /ˈhɛrəʊɪŋli/
In a manner that causes great distress or suffering.
The movie depicted the events harrowingly, leaving the audience in tears.
Harrowingly → It is formed from "harrowing" (from Old English *hergian*, meaning to harrow or distress) and the suffix "-ly" (meaning in a manner of). The word "harrowingly" means in a manner that causes distress or torment.
Think of something that causes deep distress or torment, as 'harrowing' means to distress, and '-ly' indicates the manner in which it is done.