It's usually up to the writer to find their own title, because only they know the hidden morals and meanings of their book. You should dig deep into the messages you're trying to get through to the readers and present them effectively in your title.
You can also base your title on a detail of your plot. For example, if your story is about a character writing all their experiences in a diary with a crimson cover, you could name your book 'Crimson Secrets'.
Start by listing the hidden morals and messages of your book and see where you can go from there.
I hope I helped - good luck!
