If she speaks, it will only be a pleasant word or two; should she have anything important to say, the moment will be after tea, not before it; this she knows by instinct.

The sentence wryly sketches a social code in which a woman’s speech is expected to be light, agreeable, and carefully timed. “Before tea” suggests the ritualized schedule of middle‑class domestic life, where conversation is governed by etiquette rather than urgency or intellect; anything “important” must wait for the sanctioned moment. Gissing’s phrasing (“this she knows by instinct”) is pointedly ironic: what is called instinct is really training—internalized expectations about deference, propriety, and the management of male comfort. The line functions as social satire, exposing how manners can become a mechanism of control and how self-censorship is presented as natural.