良薬口に苦し

Good medicine is bitter. ; Good advise is sometimes harsh. ; No pain, no gain.

例文

りょうやく　くちに　にがしと　いいますから、にがくても　のんで　ください。

良薬口に苦しと言いますから、苦くても飲んでください。

They say "no pain, no gain" so please take medicine even you find it bitter.

医食同源

you are what you eat
風邪は万病のもと

The common cold can develop into all kinds of illness.
慣用句

idiom
ことわざ

proverb
住めば都

Home is where you make it. (a Japanese proverb which means wherever you live, once you get used to living there, it becomes home)