Why did the queen of Narnia change from being angry to Edmund then sympathetic?

The Queen of Narnia, who is actually the White Witch, changes from being angry to sympathetic towards Edmund because she sees an opportunity to manipulate him to her advantage. She knows that she can use his desire for Turkish Delight to lure him into helping her and betraying his siblings. She feigns sympathy in order to deceive him and further her own agenda.