I'm much obliged to you for helping us.

承蒙相助，本人不胜感激。

《牛津词典》

We are very much obliged to you for doing us such a service, and mother would like to see you.

你帮了我们这么大的忙，我们非常感激，我婆婆想见见你。

youdao

I'll be very much obliged.

无任感荷。

《新英汉大辞典》

Mr. HAMILTON: (Singing) ...swing to the other side, I'm much obliged to make your acquaintance.

NPR: Anthony Hamilton: 'Ain't Nobody Worryin'

Investors will be much obliged, as the stock has made its way down to further lows in 2012.

FORBES: E-Trade Baby Looking For A New Boss: Online Broker Swaps CEO

Although firms are obliged to disclose how much investors must pay, they do not have to reveal the salesman's cut.

ECONOMIST: Wall Street