ensorĉi

A clean decode. Sorĉi, rank 1,507, is to work magic. En- is the ordinary preposition en doing prefix duty. Ensorĉi is to work magic into somebody: to put them under a spell rather than merely to cast one.

That en- is not decoration. Look at what it changes:

• sorĉi - to do magic, to cast spells. It can stand alone with no object at all: ŝi sorĉas.
• ensorĉi - to enchant a person or a place. It needs a victim, and the victim goes in the accusative: ŝi ensorĉis lin.

The prefix is doing the same job it does in enfermi, the other genuine en- build in this band: it takes a verb and points it into something.

The fairy-tale register, and the everyday one. The literal sense belongs to fabeloj - the sleeping castle, the transformed prince, the hundred years of thorns. But the figurative sense is alive and ordinary, and it is where you will actually use the word: a voice, a performance, a landscape or a person can ensorĉi you, and nothing supernatural is being claimed. English enchanting has made the same journey.

Derived forms. Ensorĉo is the spell laid on someone, ensorĉita means enchanted, and malensorĉi is to break the spell - which is the whole plot of about a third of European folklore in one four-piece word.