The phrase "a certain suspicion" is correct and usable in written English.
It can be used when referring to a vague or unspecified feeling of doubt or mistrust about something or someone.
Example: "She had a certain suspicion about his motives, even though he seemed trustworthy."
Alternatives: "a vague suspicion" or "a lingering doubt".
Yet he is treated with a certain suspicion.
"The central starting point is a certain suspicion of elites.
But Mr. Bush's circle is anticipating the encounter with a certain suspicion.
Beyond uneasiness with the concept of rankings, students harbour a certain suspicion towards their volatility.
I first moved to New York aged 11, and found my accent provoked a certain suspicion.
There is a certain suspicion of any military action post-Iraq.
But Mr Spitzer has benefited from a certain public suspicion that Wall Street was out to bilk the moms and pops of Main Street America.
'So, the only way we can be attacked is that we haven't proven case, we haven't made out a case because of certain suspicions or inferences or something like that, showing there was another man, or something like that.
Addressing certain suspicions about the suicide of a local solicitor, Canon Sidney Chambers, the new vicar of the church of St. Andrew and St. Mary in Grantchester, is reminded that "how we love determines how we live".
Near the end of the trial last year, Judge McAvoy told the jury, "The F.B.I. had certain suspicions, good and valid suspicions, for looking into Mr. Aref, but why they did that is not to be any concern of yours".
MICHELE MOODY-ADAMS: Although he wasn't always recognized to have that position, the speech before the Cooper Union sort of involves him having to really defend himself against certain suspicions that, secretly, he's really supporting the more radical abolitionists' view.
