"pleasant duty" is a correct and usable phrase in written English.
You can use it to indicate that a task is enjoyable or has enjoyable aspects to it, even if it is generally seen as unpleasant. For example, "Cleaning the kitchen is a pleasant duty when the family is all together to help out."
The young heroine of the more conventional story, derived from Italianate fiction, is wooed by a respectable young aristocrat named Claudio who has won his spurs and now considers it his pleasant duty to take a wife.
Photograph: National Gallery Ten years ago, it was my pleasant duty to serve on the panel of judges for the Charles Wollaston award, given for the most impressive work to be shown in the Summer Exhibition at the Royal Academy, and to present the prize.
My mother used to say she had the pleasant duty of keeping the Virgin Mary clean.
So striking was the orchestral sound produced by Sargent that the press thought he had retouched the scores, and Carte had the pleasant duty of correcting their error.
The mentality, he says, is that inmates need to be clued in quickly to "how the world works, and how it works is violence". No one is saying being a jail guard is pleasant duty.
Beginning Jan . 1 a pilot program will relieve some Chicago police officers of one of their less pleasant duties: taking bodies to the county morgue.
One of her pleasant duties in Alaska will be to receive an award from her friend, Edward Albee, for her body of work.
Much of the play is written with an ominously fateful logic that prefigures serious comic writers from Beckett to Joseph Heller: "Aren't there any pleasant duties?" Agnes asks the lawyer.
Recounting that one of her day's pleasant duties had been a visit to the railway station to open the offices of the company that has just acquired the London-Scotland sleeper franchise, she mentioned that 20 "high-value" jobs had been created, that the onboard food would be supplied from Dingwall and the mattresses from Aberdeen, while the new staff uniforms had been designed in Glasgow.
As the author is gradually retired from his old responsibilities of vicarious confrontation and provocation, he has grown in importance as a kind of walking, talking advertisement for the book — a much more pleasant and flattering duty, it may be, than composing the book in solitude.
