Lol, you can figure out yourself, what she would do in that case;) She dismissed him suddenly, a thing he didn't expect.She told him to go away (probably in a rude way and abruptly, because she was so annoyed of him being unfaithful.

Hi safaa This is figuratively means to send someone away ; to dismiss someone ,possibly rudely . for example:" I couldn't stand him anymore , so I sent him packing ! "

E.g. The Germans sent the Socceroos packing. Ha!

Perhaps the idea has to do with "pack up his things and leave"? It's from Shakespeare's Henry IV, part I.

I agree with Cherry. It is an informal expression meaning 'to ask somebody firmly or rudely to go away'. Amanda, who was shocked by the discovery that Jack had been unfaithful to her, sent him away.