(I chose High Fantasy, since you didn't specify. Let me know if you prefer modern fantasy or somesuch.)
She stared at the surface of the book, chewing the tip of her nail nervously. She'd stolen it from the wizard's workroom. He was getting old, and hardly even stayed awake to teach her lessons these days. It was easy to slip it under her dress, and out of the workroom. But now she wasn't sure she should even use it.
In three months, she would be wed to one of her father's vassals. She'd seen the man a number of times. Old, and not terribly entertaining. He wasn't funny, or charming. He wasn't...MEAN. He just wasn't pleasant. And Old. Too old. Mind you, she wasn't exactly young anymore, though she still posessed a youthful loveliness. SHe had full breasts and a trim waist, good arms and legs from riding and hunting with her brothers all her life, each now gone to serve another lord. Her hair was a dark brown, and her eyes a warm brown, with a smattering of freckles that made her cute instead of beautiful. At sixteen, she was as willful as she could be. She'd thrown a giant hissy fit at every other lord and vassal presented to her. Now, her father wouldn't take no for an answer. Especially since this vassal was old...and had a great deal of prime farmland on his holdings. No. Her only choice was to escape by magic. If she just killed the old man...
Lady Alexa flipped open the book to a page. The book was for summoning. She could understand enough of the language of sorcery to know that. She'd already drawn the sigil in chalk on the floor, a summoning circle. THe candles were lit, and she said the prayers of protection, every one she knew.
Standing outside the circle, Alexa began to read the strange words aloud. They were difficult, and the candlesmoke made her eyes sting, and her nose twitch. As she said the last few words to the incantation aloud, summoning up a demon she believed would rid her of the old man...
Alexa SNEEZED.