Annotations
1.
sagesse : can mean 'wisdom', but also refers more generally to propriety, prudence, good behaviour, etc.
2.
fit: simple past of faire. fit parler à Madame de Chartres: literally, he had her spoken to; i.e., he did not approach her himself, but had someone else do it.
3.
qu'elle ne pût aimer: the circumflex is crucial here, being the difference between a simple past and an imperfect subjunctive. The use of the subjunctive with the double negative expresses her mother's belief that her daughter would, indeed, be able to love her husband.
4.
articles: refers to the marriage contract.
5.
cachât: the imperfect subjunctive expresses the fact that she is not hiding anything. The sentence as a whole asserts that he could not flatter himself that she might be hiding something (i.e., hope that her feelings were stronger than she let on).