Hi,
I'm writing a story, should I use a period in the following bold sentence (and does the bold sentence contain any mistakes?):
I thought catching a criminal would be easy. Oh how wrong I was to believe it would be easy.
Or should I use a question mark because of the how?
I thought catching a criminal would be easy. Oh how wrong I was to believe it would be easy?
It's an exclamation, not a question.
Oh, how wrong I was to believe it would be easy!
Clive