I would've preferred if he started breaking the plot without knowing he's in an otome game. I quite like the villainess genre, but an assassin somehow knowing about the details of a dating sim seems contrived, and the author certainly does not care about it either, given he simply handwaved the entire thing by claiming MC's sister drilled the knowledge in his head in a single throwaway panel. Furthermore, as others have pointed out, shouldn't Liese have died in the staged accident, which took place a year before the game even started?
It's a bumpy start, but regardless, the art is nice, and a reincarnator dynamic where they can communicate with the original person's soul isn't that common, so I am interested to see where this goes.