The symbolism on the Three of Swords is scant but powerful, almost universal in its depiction on various decks. Three swords are seen piercing a heart, or occasionnally a flower, both of which are symbols of emotion and beauty. Thus the Three of Swords depicts, rather unambiguously, the ability of logic and power to harm the physical body and the emotions of a person. It is not surprising that many people don't like this card because of its associations with pain and suffering. But all of the Swords cards carry a lesson, and the Three of Swords is no different. It lesson may be the most useful of all.
So many things can shatter the fragility of the human heart: words, gestures, a turned back or a deaf ear. The Three of Swords is a dark gem that has many faces, none of which are particularly pleasant. There is rejection, sadness, loneliness, heartbreak, betrayal, separation and grief. Such events feel so painful because we don't expect them, and the Three of Swords often serves as a warning sign to show when one or more of these is possible. By preparing for it, the emotional blow can be lessened or even prevented entirely. But that is not the main lesson here.
Awful as it may sound, pain is often necessary in your life. If there was no pain there would be no challenge and life would be ultimately pointless. Pain is a great motivator because it encourages you to surmount obstacles and return your life to the way it was before. Such challenges are inevitably opportunities to learn from your mistakes and grow stronger because of their teachings. The pain may cloud your vision for a time, but it the end it will allow you to see clearly, and to put the past behind you. Life will always go on, no matter how bleak it feels.
If you can start seeing pain as an opportunity to expand and learn, life will suddenly become a whole lot less painful. The challenges remain but once they are no longer perceived as negative and evil, they lose a lot of their impact and their potency. When the Three of Swords appears and it is not in reference to an event, it is likely telling you that you have the ability to conquer any pain that comes your way. And here's how: see if the pain can help you grow. If someone has betrayed you and you don't think you can ever love again, challenge that belief wholeheartedly. Don't be surprised when your heart emerges from darkness, even more capable of loving than before.