Yennefer the last wish explanation?

In the story "The Last Wish", by Andrzej Sapkowski (author of The Witcher books), a djinn is released.

At the end of the story, Geralt makes a wish that isn't fully explained in the book, but seems to result in his ongoing relationship with Yennefer.

It seems likely that this is what she is referencing (as in the comment on your question).

I've read the book. In one of the first novels (before the 5-book saga), they run into djinn, and after some troubles they are left with last wish of three, and due to the dangerous cirumstances Geralt is forced to come up with a wish, so djinn will disappear. He was already falling for Yen, but she was cold, so he states he their destinies to be bound, after which djinn disappears, they are safe, and Yen (hearing the wish) is already intrigued. Their story continues from there.

Hope that helped :)

Apparently she no longer wants to be "artificially" connected with Geralt ;)

I actually have a very solid idea of what Geralt's 'last wish' was.

It was, essentially, Ciri.

By wishing to have a child together, Geralt ensures the Djinn cannot harm them, as they both have to live in order for this wish to be carried out.

This also correlates with Yen's words "you've condemned yourself to me" and Dandelions "their fates tied together". The Djinn is also described as being very ticky to control, and wishes that arent explicit backfiring, or not working the way they were expected to.

This also correctly makes Ciri the child surprise. She wasnt just the child surprise for Duny, but also Geralt and Yen Also, before Geralt re-finds Ciri after Cintra is destroyed, he rejected her, but she was his 'destiny'.

Both Yen and Geralt also attempt to have a child together, but are unable to because they are both infertile. Despite this, the Djinn does grant their wish.

It also explains why Geralt and Yen 'break up'. They are unable to concieve, and get frustrated with each other, and also why they 'make up' when Ciri runs off to find Geralt.

Makes better sense than 'to love each other'. Although they do that in their own ways.

ANyway, just my opinion, since its not written and we'll never really know.

No. Ciri wasn't alive, Geralt knew he was promised a child under the law of surprise for the purpose of becoming a witcher. It had nothing to do with Ciri or the desire to have a child. Both Geralt and Yen know they are infertile.

They 'break up' when Geralt loses his memory and sleeps with Triss, who, I might add, used his amnesia to her advantage, because she wanted him. During this quest, if you have chosen Yen instead of Triss obviously, they actually consummate their real love for one another by breaking the last wish imposed by the djinn, and find that they do really love each other.

Of course, nothing in the game is actually canonical, so in that sense you're right that we'll never know.

Witchers and Witches cant have children, they are infertile (hope it is the right word), and djinn can make wishes go true, so i suppose this was the "magic" that Yenn wanted to remove, it is also written in the book.