넉넉한 마음 (neok-neok-kan ma-eum) – broadminded/to have a big heart
We know that 마음 means mind or heart.
For 넉넉하다, it means to be ample/plentiful.
So in a way, 넉넉한 마음 means to have a big heart or to be broadminded.
Examples:
우리 선생님은 넉넉한 마음이 있고 일주일 한 번씩 봉사해.
Our teacher has a big heart and he would do volunteer work once every week.
그 부자는 돈이 많고 넉넉한 마음이 있어서 한 고아원을 짓었어.
That wealthy man has a lot of money and a big heart so he built an orphanage.