It's difficult because they're autonomous by the computer and conversations can be cut short, but I just did it recently, without cheats, so....
As far as the options not showing, is your Sim in another relationship? And, I would doubt it, but, is the paparazzi in a relationship? Do you have any mods or CC that dictate social interactions? Have you done enough friendly interactions to achieve the "move in" option? Have you done enough romantic interactions to get to "extremely irresistible". Without mods, you need a LOT of romantic interactions to achieve any measure above alluring. And you can't mix friendly with romantic or the romantic will drop back to "okay", at least with my game (which is really annoying).