How do you break up with someone you love when you know its not going to work out?

It is not a simple thing do but if you know very well that it is not going to work ,then it's good to be frank and tell the person that you do not think that it is going to work for both you.And do not be so soft in the that your partner tells you that it's going to work you say that you will consider it,that is not the best thing to do at this stage.