as safe as houses
US /æz seɪf æz ˈhaʊzɪz/
UK /æz seɪf æz ˈhaʊzɪz/

1.
非常に安全な, 絶対安全な
very safe and secure
:
•
Don't worry about your investments, they're as safe as houses.
あなたの投資について心配しないでください、それらは非常に安全です。
•
The new security system makes the building as safe as houses.
新しいセキュリティシステムは建物を非常に安全にします。