lovestruck - how to get nonplayable sims to propose?

@aquaglyfics I've known them ask to move in together but never seen one propose. But to get around that I switch to the NPC and play as that character to get them to propose. I just move them into a lot if they don't have one, that's if you don't want them to move into the household and become playable that way.

If they are not going to be part of my households moving forward I move them back to Other Households later.