The Price of Love

I have no idea how to defeat Jessica on Hero difficulty. I almost perfectly defeated the Green player, preserving all my archers and almost all my bears, and captured the Eastern Rampart at the end of the second month. A week later, this monster arrives with 110 Knights of Isabel, thirty Serafins, and so on. There's simply no chance of defeating her with any hero. I could try using Darkness, but there's nowhere to get spells, not even in the library (the only option is to learn a spell from Zoltan, but the losses in that battle would be too great). I tried rebuilding the Cursed Castle and building up my army, but it seems her army grows exponentially. By the beginning of the fourth month, she already had 200 Knights and so on. Maybe it's possible to defeat her with a clever strategy using single units of Death Knights, or maybe I'm just missing something. If anyone has played on Hero difficulty, please share how and, most importantly, when you defeated her. And I'd like to hear from the author what the intended timeframe is for this encounter and if there are any hidden tricks... P.S. I don't think the Green player should be considered too difficult. He can be defeated even in unfavorable situations. The losses depend on how he decides to act – if he resurrects his army, the losses will be high; if he attacks with Chaos spells, the losses will be low. Here are a couple of battles for both cases + a not-so-good scenario (only Wall is available among the fire spells; Pyromancy/Lucky Charm didn't roll).