The part of a sentence "so pleasant that" is correct and usable in written English.
You can use it to describe a pleasing experience or situation. For example, "The smell of freshly brewed coffee was so pleasant that I stayed in bed for an extra hour."
The tone is so pleasant that you can hardly object.
It took a bit too long for the food to appear on one busy Saturday night, but the server was so apologetic and the windows opening onto the street so pleasant that the delay mattered less than it might have.
But it is honest, the ingredients are top quality, and the service and atmosphere so pleasant that I quickly found my goals shifting; an evening here is bound to be a pleasant one, even if the dining is not exciting.
Except for the one-way air fare, which was $240, the cheapest available, the flight was so pleasant that it could have been a business trip in 1975, rather than the waning days of 2001.
Though the service is inept if well-meaning and the food lackluster, the setting is so pleasant that lunch here is irresistible after a morning at the nearby Fine Arts Museum.
Although the space is surprisingly skimpy and the layout flawed, being in Palm Beach, at the Breakers, in such good hands, is so pleasant that it took all my professional dedication to notice the problems.
Twigg himself is so pleasant and engaging that it is hard to imagine him crushing anyone, although, to be fair, you could argue that that was the mistake made by one Michael Portillo in 1997.
"The relations between master and slave in Virginia were so pleasant," Fiske wrote, that Britain's "offer of freedom fell upon dull uninterested ears".
She's so pleasant, in fact, that her sarcasm, drug use and gross-out jokes only add to the show's sweetness without being unconvincing or unfunny.
His apocalypse is also less alarming, with robots merely choosing to "farm us or keep us on a preserve, making life there so pleasant and convenient that there's little motivation to venture beyond its boundaries".
The unfairness of the double standards for men and women regarding sexual permissiveness (what nowadays would be derided as "slut-shaming"), figures largely in the boozy, weirdly tender story of Patricia, aimlessly drifting through a life of pleasure after her divorce at age twenty-four, only it's not really so pleasant as all that.
