"sufficiently entertained" is correct and usable in written English
You can use it when you want to signify that something has provided enough amusement or enjoyment to be satisfying. For example, "We went to the amusement park and were sufficiently entertained for the entire day."
Is she sufficiently entertained, at ease? Somehow I always knew my mother and I would go on this trip with her.
Here are a few that we've enjoyed: Jinan Younis (@Jinan_Younis) @gdnstudents your blog is keeping me sufficiently entertained during revision, happy birthday & looking forward to seeing you in summer!xx May 22, 2014 Alex Dean (@AlexDean94) Happy Bday @Gdnstudents!
Hopefully the audience will be sufficiently entertained to forgive us our sins.
Could family cartoons sufficiently entertain a young generation excited by Beatlemania and the poptastic delights of Radio 1?
Neither has an abundance of ambition or, it would appear, production money, but both are sufficiently entertaining to attract some slice of the fanboy-fangirl audience.
The goal of running more than one campaign at a time is to sufficiently entertain consumers to prevent them from changing channels, turning the page or clicking a mouse.
Occupying this detached role as far as Brand's revolution is concerned is his friend Noel Gallagher, whose witheringly bewildered comments on the matter are sufficiently entertaining to be run almost in full.
All that is left is to insure that workers in voluntary servitude are sufficiently trained, suitably fed, adequately housed, media entertained, and sufficiently intoxicated and medicated as needed.
Having entertained us sufficiently, I just hope Spacey remembers in his next season that he who dares wins.
Yet another person who buys animals to serve selfish human purposes is disappointed when the animals' lives actually require upkeep and the animals do not entertain sufficiently.
While his pocket synopses of anti-Semitism, Elizabethan England, Marlowe's "Jew of Malta" and even a Baedeker of famous actors' renditions of Shylock are edifying, they are not sufficiently enlightening or entertaining.
