I'm afraid that's the only way in the current version of the game, sorry.
Well, if you're on PC and can access the savegame folder, you could upload your savegame on our discord and let me or xtone flip the responsible variable to force it, I guess.
Otherwise, if you can wait 3-4 weeks, I'm working on a final content update for the game right now, and I could add a cheat to force-unlock her (on the laptop in the MC's room), or an option to "renegotiate" later if the negotiations didn't go perfectly.
I can wait for the final update, it's not a problem, I just wanted to know how to complete the game 100%. But it's reassuring if the final update allows for forcing negotiations or using cheats :) Anyway, thanks for your quick replies, and also, your game is really good, I hope there will be more like it