IPA: /ˈsɔːrəfəl/
KK: /ˈsɔroʊfəl/
Feeling or showing deep sadness or grief.
She had a sorrowful expression after hearing the bad news.
Sorrowful → It is formed from "sorrow" (from Old English *sorg*, meaning grief or sadness) and "-ful" (meaning full of). The word "sorrowful" means full of sorrow or expressing grief.
Think of feeling 'full of' ('-ful') 'grief' ('sorrow') — that's why sorrowful means to be filled with sadness.
No commonly confused words.