～のは事実だ

A sentence or statement + (という)のは事実だ can be used when the speaker wants to express that something is true or a fact. It's generally read as "It's true/a fact that..." Creative, huh?

東京は物価が高いことだけでなく、土地も狭いので、暮らしにくいというのは事実だ。
It's a fact that not only are Tokyo prices expensive, but because it's a small region, it's difficult to live there too.

リーさんがアリスちゃんの彼氏というのは事実だけど、彼女が好きなわけじゃないでしょ。
It's true that Lee-san is Alice's boyfriend, but that doesn't mean he likes her.

私が彼のことが好きだというのは事実だが、将来彼と結婚しようと思っているわけではない。
It's true that I like him, but that doesn't mean that I've decided to marry him in the future.

ライトはヴァンパイアのは事実だけど、悪い人じゃないんだよ。
It's true that Laito is a vampire, but he's not a bad person. (or is he?)