promises to be Tonight’s meeting promises to be a difficult one.

问题描述:

promises to be
Tonight’s meeting promises to be a difficult one.

今天的会议将是困难的。
promises to be承诺做

意思是:注定了是;一定是
今晚的会议注定是个长会。

有……的希望/预示.Tonight’s meeting promises to be a difficult one.今晚的会面有可能不好应付.