なにをかくそう
to be frank with you; to tell you the truth; I'm going to lay my cards on the table
Common word Also written 何をかくそう
Expression
何なにを隠かくそう、俺おれはケモナーなんだ。
To tell you the truth, I'm a furry.
「何なにを隠かくそうとしてるんだよ」「何なにも」
"What are you trying to hide?" "Nothing."