The phrase "little doubt" means that there is almost no question or uncertainty about something. It implies a high level of certainty, confidence and belief in what is being said or suggested.
His attire and cycling equipment leave little doubt about who's sponsoring the event. (inc.com)
In the end, the so - called dialogue theory, left little doubt about who alone could end the institutional conversation. (ruleoflaw.ca)
Though not much has been disclosed, there's little doubt in my mind that this was not the work of some part - time hacker living in his mother's basement. (entrepreneur.com)