So that there is a reason that you are arguing
This a simile. This is because a simile uses like or as to compare two things. A metaphor doesn't use like or as, but it still compares things.
The word forte means to play strongly and piano to play softly, but -issimo is a suffix which roughly means "very."
Pianissimo should be your answer.
Can you attach the passage? I need it to find the main idea.
