Given the task definition and input, reply with output. In this task, given a sentence in the English language, your task is to convert it into the Japanese language.

"But we knew that the health of the president had become a source of concern in recent days," he said.

「しかし、私たちは大統領の健康は最近悩みの種になっていたことを知っていた」と彼は述べた。