If you want to let someone down easy, timing and location matter. If you're seeking to let someone down in an empathetic matter, take some time to consider the proper location and timeframe to talk to them.  Face-to-face is ideal for difficult conversations. Humans evolved to pick up on non-verbal cues and signals that are reassuring during difficult conversations. An impromptu pat on the shoulder, for example, can reassure someone he or she is essentially lovable even if this one relationship did not work out. A look of sadness on your face can help your partner see you truly care about his or her feelings, despite the fact you feel the relationship should end.  If possible, choose to have the talk at a place where your significant other feels comfortable. Choose to stop by his or her apartment to talk, for example. It may feel uncomfortable for you but giving someone a slight sense of power during a difficult conversation can help him or her digest bad news.  If you anticipate a long conversation, try to choose a time where the conversation will not be cut short by external factors. Do not, for example, break up with your longterm boyfriend an hour before he has to leave for work. Instead, choose to stop by his place shortly after dinner on a weeknight. This will allow any lingering loose threads to be addressed. If you're letting someone down easy, you need to take full responsibility for your decision. Oftentimes, people feel it will be easier if their partner initiates the breakup. However, you are the one whose feelings have changed. It's your responsibility to start the breakup conversation. Trying to lead your partner to the conclusion, that you want to break up, through subtle cues is not only dishonest it can be confusing. Your partner may not get the message and begin to question him or herself as you subtly pull away. For example, if you become less physically affectionate in order to show your partner you're losing interest your partner might question his or her own attractiveness. If you want to...

TL;DR in Vietnamese:
Chọn thời gian và địa điểm thích hợp. Hãy chịu trách nhiệm. Hãy cởi mở và thẳng thắn về cảm giác của bạn. Nói ngắn gọn. Hãy đề nghị làm bạn bè, nếu có thể.