あるはずよ

there should be

→ 有る
phrase Rare #26,453
there should be Expresses confident expectation that something exists or is in a particular place. The sentence-ending よ adds emphasis; the phrase sounds conversational and may have a feminine or character-specific tone depending on the speaker.
JA: この近くに駅があるはずよ。
EN: There should be a station nearby.

英語であそこにあるはずよ

It should be over there.

— 甘い生活 (1960)

他に出口あるはずよ

There must be another way out.

— サスペリア (1977)

あるはずよ

It should be there.

— 道 (1954)

そういうあるはずよ

There should be a chapter like that.

— どん底作家の人生に幸あれ! (2019)

その中にあるはずよ

It should be in there.

— どん底作家の人生に幸あれ! (2019)