Enchantress is a midrange combo deck, with the combo being drawing absurd numbers of cards with Sythis, Harvest's Hand and Enchantress's Presence and then snowballing this card advantage into a victory. The deck can be broken down into a few parts: enchantresses, ramp, finisher, protection.
First and foremost, as we talked about earlier, the enchantresses are the cards that make the deck work. Mulligan fairly aggressively to find one (or Sterling Grove to tutor one up) because if we can resolve a Sythis, Harvest's Hand or Enchantress's Presence, we'll draw more than enough cards to undo our mulligans. Without an enchantress, the deck is prone to having games where it just draws a bunch of somewhat underpowered enchantments, never manages to find any velocity, and gets run over without doing much of anything.
Speaking of Sterling Grove, even though it tutors to the top of our deck, if we have an enchantress on the battlefield, we often can activate it, cast a cheap enchantment, and draw the card we tutored for right away, rather than wait another turn.
And one more time because it's important: don't play Solitary Confinement without at least one enchantress, and preferably two. While there are rare occasions when we need to cast it without an enchantress just to stay alive for a turn, knowing that we'll have to sacrifice it on our next upkeep, in general, we don't want to play Solitary Confinement until we get things set up, or else we risk locking ourselves out of the game, at worst, or, at best, wasting one of our most powerful finishers.
Thanks to Saffronolive for the description of the deck.
