Jaskier gets his soul mark at the tender age of 16, just like every body else. He keeps meeting new people and hoping to find the one. There's a possibility that he's already met them, before he turned 16. Then the mark would appear retroactively, showing the words that were said weeks or years ago. He'd definitely meet his soul mate again, it's the way destiny works with retroactive soul marks. It'll just be a lot harder to recognize your other half.

It all starts with sweatpants. Geralt and his assistant, Jaskier, have perfect professional relationship. Then, during a business trip, Jaskier knocks on Geralt's door with requested documents at 7 am. Jaskier, who is wearing comfy sweatpants and worn-out t-shirt. Geralt is doomed, he just doesn't know it yet. Oh, and then it just happens that Geralt has to pretend to be Jaskier's boyfriend. It's a very hard task. Very hard. (you can totally see where I'm going with this, right? :))

Bruce and Clark get sprayed with a sex-pollen during an interview. Bruce has already worked out an antidote (after previous encounter with it as Batman) and Clark is immune to it as an alien. Both can't risk exposing their identities, so they have to pretend to be affected by the pollen. It's not as easy as one might've thought.

That thing that Geralt and Jaskier have? It means absolutely nothing. If Geralt keeps repeating it, he might actually believe it. Though he should've known better. Or - Geralt and Jaskier fuck, Geralt is super-casual about it, highly, pointedly, definitely casual about it, until he isn't.