What does the cryptic crossword clue "Swear in debate there's no hell (4)" mean?

The definition is "Swear". The wordplay uses a deletion. CUSS (deletion) = CUSS; definition: "Swear" The answer is CUSS.

Swear in debate there's no hell (4)

Guardian Cryptic #28921 | 6 Down | 2022-11-22 flower