Given that he was a Reverend, probably resounding endorsement. With few exceptions, women - and yea, ones married to Protestant church authorities - didn't write things of which their husbands would disapprove in 1894. At least, certainly not tractates of this nature.
In the way that one knows most things one claims to know that are not vindicated through literal, sensory first-person experience - through some sort of inductive web of personal interactions, accumulated scholastic perceptions, second-hand anecdotes, lore, etc. I could certainly be wrong.
