朱に交われば赤くなる（しゅにまじわればあかくなる）

Japanese vocabulary

Meaning: people will take on the characteristics of those who surround them; spend time with the wise and you will become wise, but the friends of fools will suffer; when mixing with vermillion, one becomes red

See it used in real works

• Example sentences from Japanese novels & web fiction (Massif)
• Hear “朱に交われば赤くなる” pronounced in real videos (YouGlish)