"She is beside herself."
Translation:Elle est hors d'elle.
The English? It's a figure of speech, meaning completely at-a-loss, dismayed, upset, confused, angry. It's a little hard to explain, but it usually means extremeness of emotion: "He was beside himself with rage"; "She was beside herself with joy." Imagine that your emotions are so strong that you have no control over your response: it's like you're just a spectator, watching yourself "from the outside."