In The Metamorphosis by Franz Kafka, in Part One how does the passage starting with "It was very easy to throw off the cover..." create an air of verisimilitude?
Verisimilitude is defined in two ways. First, having...
...the appearance or semblance of truth; likelihood; probability.
...something, as an assertion, having merely the appearance of truth.
In Franz Kafka's The Metamorphosis, a great deal of what one perceives about the story has a direct correlation to which definition one chooses. Some critics suggest that this story is allegorical, and Gregor really does not change. Others suggest (and the narrator notes that Gregor does wake from "unsettling dreams" in the first paragraph) that this is only the remnant of a dream. For these readers, it would seem the second definition fits: there is only the "appearance" of truth.
However, if the reader takes the story literally, then the first definition would best apply: that what Gregor describes is taking place.
If anything creates an air of improbability, it is that Gregor has become a gigantic insect overnight, while he slept—seemingly without warning.
However, that which makes his story quite believable is Kafka's precise manner in placing his human self into the position of an insect on its back, and having the narrator incorporate these very specific and realistic details into the story. There are several phrases that bring the sense of a real man-sized bug to mind—concentrating on the details of his new insect behavior:
...all he had to do was puff himself up a little, and [the cover] fell off by itself.
The imagery that grabs my attention no matter how many times I read it is:
He would have needed hands and arms to lift himself up, but instead of that he had only his numerous little legs, which were in every different kind of perpetual motion and which, besides, he could not control.
This always brings to mind a beetle of some kind, lying on its back (like a helpless turtle) trying to gain purchase on something so as to turn itself from its vulnerable position, onto its belly so its tougher back might protect it. And while I imagine all this, I can see the tiny little legs—with the nasty, grasping Velcro-like pads at the bottom of those legs that hold fast to clothing, hair or skin—desperately scrabbling to turn itself over.
The description continues as Gregor tries to learn to control those legs: which he can manage for a short time, but only one leg at a time. There then follows the painfully slow process Gregor endures in trying to get out of bed.
Convincingly, these specific details make Kafka's story plausible—if not in real life, at least enough in fiction that the reader is persuaded to invest the time and a suspension of disbelief into finishing the story to see what happens.