Les Liaisons dangereuses (Dangerous Liaisons) Part 2, Letters 51-55 Summary

Letter 51: The Marquise de Merteuil to the Vicomte de Valmont

The Marquise is miffed because Valmont has been ignoring her. She wants him to work on keeping things going with Cécile and Danceny.
Cécile has told everything to a priest in confession.
The Marquise can't go against the advice of the priest without compromising herself, so she tells Valmont to push Danceny to continue his pursuit of Cécile regardless of what the priest has said.
Danceny still loves Cécile and she loves him back.

Valmont asks Madame de Tourvel whether or not she believes in the sincerity of his love.
He claims that his enslavement to love is not wrong but the calling of his heart.
He's been a drifter without a purpose in life—until he learned to love.
Now all he wants is to be virtuous. How can she refuse him?

Danceny is less confiding than Cécile. He won't reveal the name of his girlfriend to Valmont, but Valmont hope to get more info when he takes Danceny on a trip to Versailles.

The Marquise's plot is put into action. She leaves with Madame de Volanges so that Cécile and Danceny can have a rendezvous.
Trouble brews when Madame de Volanges becomes ill and needs to return home.
Merteuil delays leaving, knowing what's going on at home.
When they arrive back home, the young ones have kissed and made up.
The Marquise thinks that Danceny is a terrible boyfriend because he hasn't forced Cécile to go far enough.
But she's confident that she'll be able to influence Cécile to get what she wants.

Cécile confides in Sophie that she's secretly back with Danceny.
She justifies the relationship on the basis of love, telling Sophie that she'd understand if she was in love herself.
She wishes she weren't engaged to Gercourt.
In closing, Cécile tells Sophie that their friendship is a childhood one, whereas her friendship with Merteuil is an adult friendship.
But she still loves Sophie anyway.