Just adding an additional info here. You'll know what Google Font that supports the language by selecting the language in the Google Fonts site: https://fonts.google.com/?
If you don't select a Google Font or the element you pasted in uses a font family that doesn't support Chinese, the Chinese character will fallback or use a system font that supports Chinese characters. If there's none in the system, it will display a square character so it would be best to select a font family that supports Chinese.
Hope that helps.