Remove Curse: A spell to remove any one curse or evil sending. Note that using this spell on a "cursed sword", for example, would make the weapon an ordinary sword, not some form of enchanted blade. Range: Adjacent to the object.Remove Curse is pretty straight forward: one curse on one object; object must be "adjacent", which I'd define as "within touching distance, even if not touched"; and the effect is permanent.
The phrasing of the spell is a little odd, though. The spell removes any one curse "or evil sending". What's a sending, in the context of D&D? I suspect the intention was that, if a victim is haunted or stalked by a supernatural being, Remove Curse would free them. For example, a nightmare hand could be driven away with a Remove Curse spell. I would say that the difference between a curse and a sending is that a curse is in the victim or some place or object afflicting the victim, while a sending is a spell, spirit, or creature that pursues the victim, so a sending can only be dispelled while it is present (and probably attacking its victim.)