There's no need to severely care what doesn't belong to you.

There's no need to severely care what doesn't belong to you.
There's no need to severely care what doesn't belong to you.

There's no need to severely care what doesn't belong to you.
不属于自己的,又何必拼了命的去在乎.
severely是激烈严格的,这里翻译成拼命地

没有必要去认真在乎（关注）不属于你的东西

不属于你的东西，不必太在意。

没有必要太关心不属于你