Since Anne's Porter story "The Jilting of Granny Weatherall" is built around the combination of limited narration and interior monologue, the reader is boxed into a special "corner" of the total situation within which the story-as-a-whole takes place into the consciousness of the protagonist who is in a very particular state of mind: as a dying person, Granny Weatherall is losing her powers of deliberate control over events (including the events that constitute her conscious experience, which she has evidently learned to master along with the various disappointments that life has dealt her) but she is also subject to a number of intense anxieties.
Granny's Weatherall stream of thoughts and feelings is governed by associations driven by hopes and fears. Hope of not dying without first taking care of all her businesses, specially of George (the man who jilted her) and fear of her children founding out that she was not the woman they thought she was.
But, very deep in her heart, Granny's Weatherall worst fear is to loose control over her thoughts and emotions because she never could forgive George, forgot him nor stop loving him. And that is her truth, the hurtful feeling that accompanied Ellen all her life and impeded her from being happy and from loving again. In a way, the day that Ellen was jilted was as if something died inside her because she kept that feeling all her life. I think that is the reason why she became aware that she should never aloud herself to feel pity for her being jilted. She died just a little when she decided to control her feelings and thoughts in such a manner that she ended denying what she really felt.
Of course, she could not stop the steam of life, she married with John and had children, but the true is she never got over George, and when John died she felt abandoned and alone again, maybe not with the same intensity that she felt George's jilting but certainly it hurt her and she became a bitter woman.