Sentence:  That she was not immediately ready, Emma did suspect to arise from the state of her nerves; she had not yet possessed the instrument long enough to touch it without emotion; she must <WSD>reason</WSD> herself into the power of performance; and Emma could not but pity such feelings, whatever their origin, and could not but resolve never to expose them to her neighbour again. 
Meaning of the word marked with <WSD> tags:  To persuade by reasoning or argument.