The phrase "really a pity" is correct and usable in written English.
It is used to express the idea of being sorry or regretful about something. Example sentence: It's really a pity that summer is almost over.
"It's really a pity what they are doing," Mr. Vorpahl said.
It is really a pity for such a big football country not to be part of important discussions that define the future of Europe's most important competition.
"It's really a pity — since it is a huge potential from a market perspective but also societal.
"It's really a pity that we were not able to sound both of them," says Ciarletti, a planetary scientist at LATMOS-IPSL, a research institute near Paris.
It's really a pity because this would have been interesting to be in and to be at, but now we have a reading event at the same time.
It isn't Showgirls bad, which really is a pity.
It just really is a pity the UK government didn't try and resolve this without us having to come all the way over".
It really is a pity: this is such marvellous hardware - let down by the failure to identify how good software should behave.
It really is a pity we can't harness Kyle Reese's time-travelling machine and head back to the early 80s, where a young and innovative film-maker has just wrapped Piranha 2: The Spawning ….
The Toronto Star reports that Grunfeld is "a 22-year-old in her final year at York [University]." That really is a pity.
