Interesting English idioms:

1) 三度目の正直
(USA) => 3rd time's a charm!
(UK) => 3rd time's lucky!
Example: I tried the TOEIC exam 2 times already, hopefully 3rd time lucky! 🙂

2) 隣りの芝生は青い The grass is greener on the other side. Example: I really wanna live in Australia it seems so perfect but perhaps the grass is greener...hmm....

Silence is golden.
Example: I like living in the countryside, it is peaceful. As they say, silence is golden.

4) Actions speak louder than words
Doing something is better than talking about it
Example 1: I heard you yesterday and I heard you today saying you will write the report asap however you've not done it yet, 
remember actions speak louder than words. 
Example 2: I know you say you love me, but I don't see it, show me your action, after all actions speak louder than words.

5) You can say that again
I totally agree with what you're saying
Example 1: (Suzuki san almost crashed his car) Wow that was close Suzuki san, you could have died!
''I know David, you can say that again!''
Example 2: If this weather gets any hotter, I'll get sick! 
''You can say that again!''