This is the 591st most frequent Polish word.
wcale
"Not at all" or "actually" (depending on context).
The word 'wcale' emphasizes the negation provided by 'nie', meaning 'not at all'.
Nie jestem wcale zmęczony.
I'm not tired at all.
Here, 'wcale' strengthens the statement of not knowing, indicating total negation.
Wcale tego nie wiedziałem!
I didn't know that at all!
'Wcale' is used here to deny the perception of difficulty entirely.