Sentence:  At length [...] the Duke demanded to know of Durward who his guide was, [...] and wherefore he had been led to entertain suspicion of him. To the first of these questions Quentin Durward answered by naming Hayraddin Maugrabin, the Bohemian; [...] and in reply to the third point he mentioned what had happened in the Franciscan convent near Namur, how the Bohemian had been expelled from the holy house, and how, <WSD>jealous</WSD> of his behaviour, he had dogged him to a rendezvous with one of William de la Marck's lanzknechts, where he overheard them arrange a plan for surprising the ladies who were under his protection. 
Meaning of the word marked with <WSD> tags:  Suspecting, suspicious.