I just saw the worst act of betrayal on a game-show.
The Sun
But the process by which these documents have become public unquestionably began with an act of betrayal.
Times, Sunday Times
This act of betrayal, however, turned out to be a total pleasure.
Times, Sunday Times
It can't simply be seen as an act of betrayal, she says.
Times, Sunday Times
It involves an act of betrayal, or perhaps a kind of coming out.
Times, Sunday Times