How can I convince my best friend to move in with us?

I mean she had a good job but she’s making excuses that she still can’t afford to move out but I told her that we can split the rent so she doesn’t have to pay so much. Every time I bring it up and want to discuss it with her she always gets an attitude and change the subject. She doesn’t want to live with mommy and daddy forever does she?
I’m not trying to push her but I was trying to encourage her to get out of her comfort zone and start living and becoming an adult. Cousin says that it would be a great idea for her to get her comfort zone and make sure she’s ready. She’s the only one that I asked to be roomies because number one, I trust her a lot more than anyone else, two i’ve known her since childhood and three she’s never done anything to go behind my back. The other friend we had left us. She’s the only one that I trust besides my cousin that I live with. It’s up to her though.
Rent is not bad it’s only $700 a month.
My cousin and I split the rent, $350 each so if she decides to move in with us the it would be about, $233.3333 whatever each. I’ll just say $233. It isn’t bad. That’s why I keep telling her to have an open mind and don’t give up so easily and there’s always affordable places.