'I don't mind,' he said carelessly.

“我无所谓。”他满不在乎地说。

《牛津词典》

'I don't mind,' she said, without much enthusiasm.

“我不在乎。”她不冷不热地说。

《牛津词典》

You can say something like, "I remember you said something very interesting yesterday and wanted to talk about it some more, but I'm new here and don't remember your name yet. Would you mind telling me again?"

你可以这样说：“我记得你昨天说了一些有趣的事情，还想多谈谈，但我是新来的，还不记得你的名字。你介意再告诉我一遍吗？”

youdao

"I guess Quinn will win, and I don't mind, " said author Salman Rushdie.

WSJ: New York City Mayoral Candidates as Cause Celebrities

I've never seen one minute of doubt in his mind, not one minute where he said 'I don't want to do this'.

BBC: Eduardo delight at dream comeback

"I don't mind it, " Tabatha said of her pet's celebrity.

CNN: The unlikely star of SXSW: Grumpy Cat