だとわかる

can tell that; realize that

→ だ
phrase Uncommon #19,743
can tell that; realize that Used after a statement to say that you can tell or realize something is true.
JA: この事実から彼が正直な人だとわかる。
EN: From this fact, you can tell that he is an honest person.

それらの手紙を見るだけで、彼女が誠実な女性だとわかる。

Just by looking at those letters, you can tell that she is an honest woman.

奥には、パン屋だとわかる部屋。

At the back is a room that you can tell is a bakery.

この事実から彼が正直な人だとわかる。

This fact shows that he is an honest person.

星船の基準で見れば、私たちはひどく貧しい場所だとわかるだろう、と私は思った。

I thought that by Starship standards, they’d find us terribly poor.

どうして彼だとわかるの?

How do you know it’s him?

— ミスティック・リバー (2003)

少し考えれば、その計画全体は問題外だとわかる。

With a little thought, you'll see that the whole plan is out of the question.

はいでもどうして彼女がいい人だとわかるの?

Yes, but how do you know she’s a good person?

— तुम्बाड (2018)

彼のなまりから外国人だとわかる。

You can tell he’s a foreigner from his accent.

ズボンをはいてなくてもランチョーはお前だとわかるさ

Even if you weren't wearing pants, Rancho, I'd know it was you.

— きっと、うまくいく (2009)

裏切り者の素性を追ってみれば、その裏切り者が家族の厄介者だとわかるでしょう。

If you look into the traitor’s background, you’ll find that they’re the black sheep of the family.