In fact, there was suspicion, and Rachel was beginning to suspect what that suspicion was.

She could not say absolutely that she did not entertain it herself for a single instant.

She had entertained and had dismissed the thought a good many times.

Why had he never told her his real motive in marrying her?
Some subtle motive there had been; why could he never tell her what it was?
Then there was his intimacy with her first husband, which she had only discovered by chance, after the most sedulous concealment on his part.

And, finally, there was the defiant character of his challenge to Langholm, as it were to do his worst (not his best) as a detective.
On the other hand, there was that woman's instinct which no wise woman disregards; and Rachel's instinct had never confirmed her fancies in this matter.