I'm looking for another idiom similar to:
not have the faintest idea
It should be able to start a sentence. For some reason I want to use "by the stars" but I don't think this means anything, but if it did, the sentence would look something like this:
By the stars I have no clue how he came to that conclusion.
I guess the idom would more so mean "in utter confusion" like:
In utter confusion I have no clue how he came to that conclusion.
Best Answer
"By the stars" would not necessarily suggest that the speaker has no idea. It sounds more similar to "By Jov" or "Oh my God" which can suggest a pretty wide array of reactions, from surprise and bewilderment to outrage. Also, using it the way you want to can even come across as a type of truism, since the general meaning of the sentence it will be used in is that the speaker has no clue, so there is no need to use it both as an opening line and then reiterate it several words later.
"By the stars" is a nice choice of idiom to express the speaker's surprise, so you can keep using it, as long as you agree to let go of the intended meaning of "I don't have the faintest idea". It just makes the sentence it's used in sound needlessly convoluted and there's a very good chance that your readers will not understand it the same way you intended it.