The phrase 'they confirmed to' is correct and usable in written English.
It typically means that someone or some organization provided an affirmative answer or solution to a request, question, or situation. For example, "They confirmed to me that the meeting will start at 10am tomorrow morning."
But yesterday, they confirmed to WTA Tour officials that they would play in Munich.
They confirmed to MediaGuardian: "I am speaking to a Californian lawyer tonight who has expressed an interest in representing me pro bono".
They confirmed to me, by comparing photos, it was definitely Bob. Bob Robinson was Jacqui's first love and the father of her eldest child.
"Last night we saw them leave, and this morning they confirmed to us that they had gone toward Baghran," he said.
(Immediately after the incident, she spoke with two people; they confirmed to me that she had described her experience to them at the time).
While the pair didn't go into detail about their methodology, they confirmed to Reuters that Google "tracks the state actors that attack our users".
They confirm to have developed technical skills related to the discipline and to have improved their teamwork skills.
This is Olympic charter, and the I.O.C. communicates with the authorities of Russia, and they confirm to us there will be no question at all.
At SAP, the project development teams work independently; e.g., they choose their own development model and tools, as long as they confirm to the corporate requirements, such as the global security policies.
But they confirm to our 21st-century ideas of what science fiction should look like: everything cast in gleaming blacks and silvers, all piercing lasers and hostile environments.
"When the officers arrived they quickly confirmed to Borders staff that police had no interest in the matter.
