I'm not doubting your story, I just have a few clarifying questions to ask.
I am now doubting your honesty.He was doubting his actions that day.
I was doubting that she was telling the truth^ In this answer doubting is used as a verb. The word doubting can be used as a verb (somehow informal because DOUBT is a stative verb). It can also be used as an adjective according to some dictionaries (although dubious would be the best word)It was a very doubting/dubious answer (an adjective)
DOUBTing
Doubting
I told Ben that the butterfly finally emerged from the cacoon, but he was a doubting thomas and needed to see for himself.
To use the doubting Thomas idiom in a sentence, you might say "Fred wouldn't believe in a ghost unless he saw one himself, he is such a doubting Thomas. " The idiom refers to a person who will not believe something without strong evidence.
I told Kim that the tickets had been found, but being a doubting Thomas, she wouldn't believe me until she saw them.
Wondering about the veracity of something
The term for this is cynicicm, and the person is a cynic.
Faith-doubting holy man who encounters a case of demonic possession that could turn out to be real.
Doubting is two syllables. The b is silent.
Doubting Thomas - song - was created in 2005.