YA sci-fi/fantasy about a girl placed in a sort of simulation? Falls in love with one of her captors, which is an alien

[Jorien]

My memories of this are very vague, but I'd say I read this about +/- 7 years ago? It had some hungergames-vibes. A girl was chosen or captured and had to participate in some sort of games with other kids in a constructed world. There was a system with coins as rewards I think. Her captors were some sort of aliens and she fell in love with one of them. There was a significant scene near the end of the book (or last book? I don't remember if it was a series or a standalone) that took place in the water. With her and this alien dude.