Sentence:  Mr Jones expressed great gratitude to the lady for the kind intentions towards him which she had expressed, and indeed testified, by this proposal; but, besides intimating some diffidence of success from the lady's knowledge of his love to her niece, which had not been her case in regard to Mr Fitzpatrick, he said, he was afraid Miss Western would never agree to an imposition of this kind, as well from her utter detestation of all <WSD>fallacy</WSD> as from her avowed duty to her aunt. 
Meaning of the word marked with <WSD> tags:  Deceptive or false appearance; that which misleads the eye or the mind.