Can she legally take back the furniture she gave us?

so this women moved in with me and my fiance and gave us her couch fridge hutch table set shelving and told us that would pay for the rent for the 3 months she lived with us..now she's found a place and wants it all back..she hasn't lived here in 2 months..so the furniture's been here 5 months..and threatening to call the police if she doesn't get them back..how can we prove she gave it to us without recites?also whats the legal mount of time something can stay in someone's house and then it becomes there's? thanks