Fiancé keeps saying she doesn't want to marry me

[ApolloApollo]

So just now is about the fourth time she's said this.
I was trying to take our daughter downstairs to give her some rest, she kept saying no go away no.
I said please I wanna see her and then she said no go away don't wanna marry you go away.
She always throws it out when she's getting annoyed or upset
Aibu to be wondering why and to be v hurt by it

Have you asked her why? In a quieter moment?
If she doesn't mean it then you need to explain how hurtful it is to have it said in every tiff.
If she does mean it then you have a different conversation.

Aw - I'll marry you

I think you need to sit down and talk to her about it, at a time when she is not upset.