私たちは姉妹３人で喫茶店を始めた。
We three sisters opened a coffee shop.

なるべく姉ちゃんにも周りにも迷惑をかけずに、事態の早期解決をなんとか頼むぞ。
I want you to somehow resolve the situation as promptly, as much as possible avoiding causing trouble for my sister and those around us.

例えば、大阪はサンフランシスコの姉妹都市です。
For example, Osaka is the sister city of San Francisco.

兄が急逝したのは２年前、義姉は一人兄の遺した小さな宝飾店を健気に守ってきた。
Since my brother died suddenly two years ago, my sister-in-law has valiantly kept going the small jewellery store he left her.

彼らの学校と私たちの学校は姉妹校です。
Their school and ours are sister schools.