4. “You deserve better.”
This line gives the impression that the breakup is amicable. However, the dumpee will resent you for saying it, and your Japanese girlfriend might think, “What I deserve is none of your business” or “I don’t need to hear that from you.” Your girlfriend might even resist the breakup, thinking “But why don’t you get that you are the one I want.” This breakup line can create a vicious cycle, so it’s best avoided.