True fear is hard to convey, especially when writing a scary story. Sure, you can state that your character feels fearful, but fear is an art form better shown than told. And merely repeating the words “fear” and “dread” and “horror” and “panic” and “fright” and “alarm” and “scare” isn’t going to cut it.
You could go with the classics of rattling chains, splattering of blood and tormented groans. But that’s all been done before.
What you want is to chill your readers to the core. You want to see goosebumps. You want to haunt their nightmares.