What is the point of the Tavern story

In “the things they carried”, why is jimmy unsure when martha calls the pebble “a token of her truest feelings”

The following passage is an example of what type of text structure tornados are caused by unstable air interacting with the wind sheer the resulting formation can cause devastating effects

Even the insistent cough of the woman next to him wasn't enough to draw his eyes away from the tiny type of the ancient book its pages were brittle and felt like they could crumble at the slightest disturbance he noticed the musty odor if each page as he carefully it over.