Cryptogram from Frankenstein; or, the modern prometheus, chapter 20

I started forward and exclaimed, "Villain! Before you sign my death-warrant, be sure that you are yourself safe."

The sentence you are solving goes here.

All was again silent, but his words rang in my ears. I burned with rage to pursue the murderer of my peace and precipitate him into the ocean. I walked up and down my room hastily and perturbed, while my imagination conjured up a thousand images to torment and sting me. Why had I not followed him and closed with him in mortal strife? But I had suffered him to depart, and he had directed his course towards the mainland. I shuddered to think who might be the next victim sacrificed to his insatiate revenge. And then I thought again of his words - "I will be with you on your wedding-night." That, then, was the period fixed for the fulfilment of my destiny. In that hour I should die and at once satisfy and extinguish his malice. The prospect did not move me to fear; yet when I thought of my beloved Elizabeth, of her tears and endless sorrow, when she should find her lover so barbarously snatched from her, tears, the first I had shed for many months, streamed from my eyes, and I resolved not to fall before my enemy without a bitter struggle.