The Creole culture that Edna finds herself a part of at the beginning of the story is one that she struggles to fit into. The people she is with live their life in a communal way, so much so that Edna is shocked at the way that they talk about anything and everything together and do not keep things to themselves. This is exemplified by a book that Enda finds and reads:
A book had gone the rounds of the pension. When it came her turn to read it, she did so with profound astonishment. She felt moved to read the book in secret and solitude, though none of the others had done so,--to hide it from view at the sound of approaching footsteps. It was openly criticised and freely discussed at table. Mrs. Pontellier gave over being astonished, and concluded that wonders would never cease.
This is of course one of the central differences between Edna and the other characters who are part of this Creole culture. Edna is a character who is at heart very private and to whom solitude is very important. She is thrust into a society where there is an expectation of openness and communal life that she finds oppressive. This is something that can be seen in the symbol of the sea, which calls to Edna at various points to the text with a "seductive" voice. The importance of the symbol of the sea can be seen in its final image, before Edna enters it to drown:
The voice of the sea is seductive, never ceasing, whispering, clamoring, muttering, inviting the soul to wander in abysses of solitude. All along the white beach, up and down, there was no living thing in sight.
Given Edna's love of solitude, this scene is the perfect one for her final ending, as it gives her the freedom to be utterly private and to live her last moments out of the public gaze that it is impossible to escape in the Creole culture she is forced to become a part of. Reserve is therefore seen in the character of Edna and her struggle to escape from the restrictions of the society she finds herself a part of.