一定能，必定会
used to say that something will certainly happen
If we persevere, we cannot but succeed. 如果我们坚持不懈，就一定会胜利。
If we remain true to ourselves, we cannot but prevail.
With people of this calibre on our side, surely we cannot but win.
You cannot but wonder how much of the script is based on fact.
Having learned what she went through as a young woman, you cannot but feel for her.
See also: cannot