Something that is inevitable is something that can't be prevented to happen. It's something that will occur.
Remember conflict refers to an obstacle all challenges that prevent one from accomplishing his or her goals. It also means disagreement with all differing views between two or more people.
In Black Hermit, we find that the conflict between Remi and his parents is inevitable. When Remi was told to inherit the wife of his deceased elder brother, he refused. This is because of the education he gained which provided a different viewpoint from his tribe. He knew he had to choose a lady to be his wife, not to be forced. His hatred for his mother was a result of it.
The village woman couldn't convince Thoni not to commit suicide because Donnie wanted to be dead. Tony had wanted to be dead since she was young. She had a longed to be in the presence of darkness where she could not see anyone and no one would see her all know that she exists. Therefore, Thoni's desire to be engulfed in darkness is something that she had planned for a long time. The woman couldn't prevent it from committing it.