There seems to be no mention of something that Jane does that frightens Mr. Rochester in this chapter, and I wonder if you actually mean irritate instead. Let us remember that this is the chapter that comes directly after Rochester's proposal, and in this chapter Jane is counseled by the well-meaning Mrs. Fairfax, to keep herself as distant from Rochester as possible until they are actually married:
Try and keep Mr. Rochester at a distance: distrust yourself as well as him. Gentelmen in his station are not accustomed to marry their governesses.
Accordingly, when they go into town, Jane insists that Adele will accompany them, even though, as Rochester says, she will be a "restraint." Even after playing the piano for Rochester to sing a love ballad, Jane manages to control her feelings to avoid a romantic scene:
He rose and came towards me, and I saw his face all kindled and his full falcon-eye flashing, and tenderness and passion in every lineament. I quailed momentarily--then I rallied. Soft scene, daring demonstration, I would not have...
Jane decides to heed Mrs. Fairfax's advice, and thus we can certainly see that she irritates Mr. Rochester, even though there seems to be little evidence of her frightening him.