Answer:
The author's use of "No matter" implies his optimism involving the removal of the stain.
Explanation:
I don't have your passage, so I can't give you a full answer. However, the term "no matter" suggests that no matter what it takes, the stain will be removed.
It's an example of personification. :)
A roadside manual for how to change a tire would be much more simple in the explanation than it would be in the owners manual.
