A heart is pierced by three swords. A storm rages on over an angry sea in the background.

You can be "in two minds" about something, but this heart is in greater difficulty, being pierced, as it is, by three swords. No wonder the storm is raging! :) And of course, swords being such an intellectual suit, it's only natural that when they encounter the heart, there will be much conflict. The mind versus the heart, a sure source of conflict.

In numerology, the number three is considered to be a very strong one (associated with the triangle, a highly resistant shape, and all that). In "proper Kabbalistic" terms, the number three is the first of the Sephiroth to manifest as form (Kether and Chokmah being concepts rather than forms) The encounter between Binah (the giver of form) and the intellectual swords will create conflict as they both try and dominate the other. A bit like a horse being broken, really, where the energy of the horse is being given form as service to the rider. The three swords consitute a powerful presence, numerologically speaking. The conflict will not go away or be resolved by itself. In fact, whether the card is reversed or not makes no difference. It's ALL conflict, all of the time. And THAT's why the card reads "Sorrow".