Well, at least he acts as though she is intended to find that reassuring.

"How lucky for me, to be so unique." She keeps her voice soft, so that the tone stops just short of actually sarcastic. Indeed, the fact that her statement is simultaneously honest -- yes, she is lucky to have this; why would she ever think of giving it up? -- and resentful is, if anything, a suitably accurate representation of her feelings on the matter.

Then, a meaningful pause. She won't pretend to know the first thing about sorcery, much less this Elene brand of it. Presumably Martel understands her so-called requirements by now; if not, then it is quite clear that he won't be hesitating to ask. In the end, he's leading the dance, and she'll wait for her cue.