Sentence:  It was unusual with Margaret to <WSD>obtrude</WSD> her own subject of conversation on others; but, in this case, she was so anxious to prevent Mr. Thornton from feeling annoyance at the words he had accidentally overheard, that it was not until she had done speaking that she coloured all over with consciousness ... 
Meaning of the word marked with <WSD> tags:  To proffer (something) by force; to impose (something) (on) someone or (into) some area. (from 16th c.)