The phrase "a dedicated assistant" is correct and usable in written English.
You can use it to describe someone who is committed and devoted to helping or supporting others, often in a professional context.
Example: "She has always been a dedicated assistant, ensuring that every task is completed on time and to the best of her ability."
Alternatives: "a committed aide" or "a loyal helper."
Alongside Paul Newman and Robert Redford's con men, Mr. Durning was a crooked cop in the 1973 movie "The Sting"; starring with Nick Nolte, he was a dedicated assistant football coach in "North Dallas Forty" (1979); in the shadow of Robert De Niro, he was a hypocritical power broker in "True Confessions" (1981).
The headphones have a dedicated Assistant button, which users can push to call up the voice-based companion whenever they want.
Zirtual was founded on the idea that even the busiest of professionals probably don't need a dedicated assistant sitting at a desk for eight hours a day.
I was blessed to have a dedicated assistant like Dagga to help plow through the process.
For the moment its big strength may not be its still rather unconvincing imitation of a library, but its much better impersonation of an amiable, dedicated assistant, who takes care of the irritating details that can otherwise bring an afternoon to a screeching halt.
Marcel has been our dedicated assistant coach since 2005.
Under Gober's direction, a team of four dedicated assistants tried this and tried that and never gave up.
Physiological recordings were associated with metadata collection by a dedicated research assistant.
Google's new Chromebook -- the PixelBook -- has a dedicated Google Assistant button.
In all cases, though, Zirtual believes that it can significantly reduce the cost of hiring a dedicated executive assistant, which costs an average of $54,000 a year.
Study funding is used to ensure that each Cancer Council has a dedicated research assistant to support evaluation.
