Yes Earnest I am certain you are correct about Emma. It was not until Alfred Russel Wallace sent him a letter in which he laid out almost identical ideas about Natural Selection that Darwin decided to publish his proposed work in parts beginning with Origins.
Emma was a conventional English Christian with no interest at all in science. She bore ten children because Darwin refused to use contraception, thinking it his duty to produce as many middle-class Englishmen as possible!
The quote is interesting. Of course the advancement in science in the last 150 years has confirmed the truth of Darwin's central tenet so thoroughly that it would be obtuse to reject it as a fact. If we make concise predictions and then observe the accuracy of those in multiple independent ways then we can have a very high degree of confidence in our convictions. If the truth of evolution depended on abstract thought alone then of course it would be a concern.