IPA: /dɪˈstrɛs.fəl.i/
KK: /dɪˈstrɛs.fəl.i/
In a way that shows great worry or suffering.
She spoke distressfully about the loss of her pet.
Distressfully → It is formed from "distress" (from Old French *destresse*, meaning to be in a state of suffering or trouble) and "-fully" (meaning in a manner characterized by). The word "distressfully" means in a manner characterized by suffering or trouble.
Think of being in a state of suffering ('distress') and how that can be described as happening 'fully' or completely. This helps you remember that 'distressfully' means in a way that shows deep suffering.