How close a friend can she be if she doesn't know your apartment is tiny? Unless she does know, and couldn't care about your space or comfort. Either way, find a backbone and stand your ground. If she ends the friendship, at least you'll know the calibre of friend she was and what to watch out for in others to avoid more of the same in the future.

Be honest about it. Or let her move in. Those are your 2 options

Tell her no saying you don’t recall a conversation about her moving in. Could it be that the move in message was for another friend of hers and she sent it to you by mistake?

You should say "Yes, and don't worry about rent!" You can hope that some of her gall and confidence rubs off on you.

Maybe you were drunk during this conversation

Say no. Its really not that hard. ydi

How about saying no?

If you want her to move in, say yes. If you don't, say no.

tell her you don't know wtf she's taking about

How about no.