The most common and most likely answer to this crossword clue is the 12 letter word INFIDELITIES
I've seen this crossword clue in The Guardian
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More clues leading to the result INFIDELITIES
Buddy explains!
The straight part
We know that "Betrayals" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case betrayals = infidelities.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does INFIDELITIES mean?
INFIDELITIES noun- Unfaithfulness in a marriage or an intimate relationship: practice or instance of having a sexual or romantic affair with someone other than one's spouse, without the consent of the spouse.
- Unfaithfulness in some other moral obligation.
- Lack of religious belief.