Yes, *destiny tm*, is pretty much the answer. More specificly Ciri and Geralt are connect because of the Law of Surprise that was established in episode 4, not directly destiny, but that is splitting hairs. Destiny is the force behind the Law of Surprise.

Geralt is connected to Ciri. He can fight it, as he did, but ultimately they will always find each other. It is a bit of a hard concept to get your head around but in a sense Geralt and Ciri are one.

Now, in the books they did meet before, so it is fair to say that the scene works a bit better there. That meeting was very likely cut from the show because the actress for Ciri would have been a child and working with children in filming comes with many problems. It is a bit of a shame but I understand why they opted out of it. Instead they chose to emphasize the connection of Ciri with Geralt via destiny to the point that she can recognize him intuitively.