My girlfriend wants to break up with me as I had to go to a different place for work so what do I say to her during breakup She wants to talk to me about it tonight?

It depends on your ages; how far away you are going for work; how often you'll get to see each each other. If there is little time where you won't be seeing each other she is probably breaking off with you because people need to be together. Humans need contact and constant phone calls to text messages doesn't cut it in a long run. If there are ways you can be together more often then it's up to you to let her know that. If she still wants to break up then you are going to have to accept her decision and tell her .... 'then it couldn't have been love because people in love don't walk away because of a small obstacle. We can still see each other and keep in contact.' She may fear that you won't be faithful to her (that could happen even though you may not realize it) or, she may fear she can't be without a boyfriend for long periods of time. If you are meant to be together then you will be.