Is a person held accountable for a whisper of the word "ilah" (god), or is he considered a polytheist if he utters it aloud to himself, and is his sincere repentance accepted?

A servant is not held accountable for the thoughts that cross his mind unless he speaks them or acts upon them, due to the Prophet's (peace and blessings be upon him) saying: "Indeed, Allah has pardoned my Ummah for what they whisper to themselves, as long as they do not act upon it or speak of it." And if obsessive whispering leads a person to utter something he does not intend, then there is no accountability upon him. However, if he utters a word of disbelief knowingly, willingly, and not under duress, then he disbelieves. And if a servant repents from a sin and fulfills the conditions of repentance, then his repentance is accepted and his sin is forgiven.