Sisters with a complicated relationship

My sister is several years older than me and was cruel to me when I was little. Our relationship has been marked by her criticism of me and my efforts to win her approval. We became estranged shortly after my second child was born. We have always had a difficult relationship, and after she ghosted my older son on his birthday and was cruel to our mother, I told her by mail that I would no longer tolerate her mistreatment and urged her to see how her behavior toward her family was depriving her children of aunts, uncles, cousins, and grandparents. She told me never to speak to her or her family again.

We did not speak for about six years. Then she reached out via email to see if I'd be interested in reconnecting. We scheduled coffee, she canceled. We rescheduled, she canceled. We rescheduled, she stood me up. It was far more hurtful than I had expected. I had told myself not to get my hopes up, but I'd done that anyway. I was crushed when it didn't work out. 

Several months later, our stepfather died, and days later, the presidential election further traumatized everyone. My sister reached out again that week to suggest we try to reconcile again. I told her I was too sad and couldn't open myself up to more hurt at that time.

A few months later, she asked again. She invited me to coffee and to my surprise, she actually showed up. She told me that she wanted me to have a relationship with her now teenage daughter and younger son and for our kids to have relationships with each other. I believe she was willing to dredge up the past and try to fix it, but I am not, and we haven't spoken of it.

My two sons now consider their male cousin one of their best friends and they are able to spend time together fairly often. I am developing a good relationship with my niece and adore her.  My sister and I are still not close and probably will never have the kind of sisterly relationship either of us would like to have. We are cordial. And I think that's good enough for both of us.