This is a Cornell Woolrich story (under the William Irish name). It's about a woman who has a brief affair and then is blackmailed some years after she's married. She loses an earring during the payoff, which leads to further trouble when the blackmailer is found dead.
It's another noir from Argentina, noted by Shelby, I think.
This has a great dreamlike feeling in places, as the heroine provides some tortured voiceover. There is first rate emotional music in several places that add to the mood in important ways. I suggest listening to the score at 35 minutes in to see what I mean. There are also dark scenes now and then, as at 30 minutes, 30 seconds in when she goes to the blackmailer's apartment. The story is actually told as a flashback that begins with her burning her letters.
Ilda is her name and Roberto is her husband. The blackmailer's name is Varela.
She falls for this guy only very briefly, but strongly, saying "Something about him attracted me, in spite of myself."
It's just great how these noirs from Argentina play at this era and how they're put together. Ilda sees that she was a "romantic" an "idealist", and she tells us. We see that she had the feminine weakness for certain males, and could be swept off her feet. This is not an uncommon recognition and plot point in other movies.