"The Landlady" by Roald Dhal (Summary).

Billy Weaver arrives in Bath after taking the train from London. He's never been to the town before, but he's due to start a new job there soon and he's excited at the prospect. He heads toward The Bell and Dragon, which is a pub he's been told he could spend the night at. On the way though, he notices a sign in the window of a nearby house: "BED AND BREAKFAST." Billy looks in …

…again: "Haven't there been any other guests here except them in the last two or three years?" She gives him a little smile as she replies, "No, my dear. Only you." (If you don't get it, here's what happens: she poisoned the other two men and stuffed them. Billy has read of their disappearances in the newspaper, and now he's to be the next victim! The bitter almond taste in his tea is potassium cyanide.)