He promised Geralt that he would give him the child if it was a boy, that's actually what Geralt asked for.
Ciri was not a boy. Besides Calathne had no intention of ever allowing Geralt to gain the child and in Cintra Calanthe ruled.
“I still say I am in your debt, witcher. It is my life that Rainfarn's dagger endangered. I would have been beaten to death by the guards without you. If there's talk of a price, then I should be the one to pay. I assure you I can afford it. What do you ask, Geralt?”
“Duny,” said Geralt slowly, “a witcher who is asked such a question has to ask to have it repeated.”
“I repeat, therefore. Because, you see, I am in your debt for still another reason. When I found out who you were, there in the hall, I hated you and thought very badly of you. I took you for a blind, bloodthirsty tool, for someone who kills coldly and without question, who wipes his blade clean of blood and counts the cash. But I’ve become convinced that the witcher's profession is worthy of respect. You protect us not only from the evil lurking in the darkness, but also from that which lies within ourselves. It's a shame there are so few of you.”
Calanthe smiled. For the first time that night, Geralt was inclined to believe it was genuine.
“My son-in-law has spoken well. I have to add two words to what he said. Precisely two. Forgive, Geralt.”
“And I,” said Duny, “ask again. What do you ask for?”
“Duny,” said Geralt seriously, “Calanthe, Pavetta. And you, righteous knight Tuirseach, future king of Cintra. In order to become a witcher, you have to be born in the shadow of destiny, and very few are born like that. That's why there are so few of us. We're growing old, dying, without anyone to pass our knowledge, our gifts, on to. We lack successors. And this world is full of Evil which waits for the day none of us are left.”
“Geralt,” whispered Calanthe.
"Yes, you're not wrong, queen. Duny! You will give me that which you already have but do not know. I’ll return to Cintra in six years to see if destiny has been kind to me.”
No mention of a son or specifics. Duny said he could give Geralt what he wanted and Geralt asked him to repeat it. Calanthe's opinion is irrelevant under the Law of Surprise.
We know Emhyr is a scumbag because of his desire to save the world by incest against an unwilling kidnapped girl.
What we argue is whether he is a man of his word.
And he's not.
Letho's betrayal is perfectly in character.
You know I would violate every fucking law and oath if it means to save my daughter from being mutilated in the Trail of the Grasses. Emhyr is Ciri's father, there is simply no way around it. But I consider Geralt being Ciri's foster parent/mentor/guardian not because he taught her witchering, but exactly because he realized that it was not a good life for her (with all these dress masquerades and inevitable changes), and sent her and Yen to Ellander. All the time he tried to save her from danger, and I would imagine he shouldn't be really thrilled if Ciri chooses to fight manticoras, wraiths, and all, for the rest of her life. I know I wouldn't.
Except, of course, he intended to marry his child from the very beginning.
On a basic level, I don't think Emhyr not being a man of his word changes anything. Lots of Northerner kings are liars.
I'm just surprised fans try to portray Emhyr as having any big sense of honor.
He's NEVER been honorable.
He's been EFFICIENT and RUTHLESS and POWERFUL and INTELLIGENT.
Why can't we respect him for that?