'There's no 'good' way to break up with someone'

Is there a good way to end a relationship with someone without hurting them too much? I want to say it's over, but am not sure how to send the message across.
I'm not sure what you mean either. Do you want to send this person an SMS? Use a sad emoticon on WhatsApp? The end of a relationship is never going to be painless, unless both people involved believe there is no future together.

I have been dating a girl at my office for a few months now. No one knows about it, because we are not sure about the company's HR policy on co-workers dating, but we have been thinking about mentioning it to people to avoid awkward situations where they run into us at a restaurant or something. Is this a good idea, or should we just keep it professional at work? We are not sure what happens if people start guessing that we are a couple.
Some companies do have issues with people dating, but a lot of these strange rules come from HR personnel who, to be honest, have very little to do at any office and must, therefore, spend their time thinking up regulations like these. I don't know what your office is like but the possibility of co-workers finding you two together outside shouldn't be an issue considering you are both adults with lives outside the office space. What you do outside the office is your own business, or should be. I would recommend keeping things professional at the office always, as far as possible, simply because your colleagues are not your friends. If they are, there's no harm in informing them but, if they are just people you work with, your personal life is really none of their business. If you both feel uncomfortable about this, do keep in mind that informing others may, at times, make them assume you are not being professional about some things even when you are. So think about that before you make a decision.