Hello teacher.
Can I ask you questions?
I have two questions.
Q1.
Does the following two sentences have exactly the same meanings?
1-1 Something that is circumstantial is related to a particular circumstance.
1-2 Something that is circumstantial relates to a particular circumstance.

Q2.
What does sentence 2-1 mean? Is sentence A right, or sentence B?
2-1 He is sincere in his view.
A) He think himself of being sincere.
B) His suggestions, opinions, or advices are sincere.