seal someone's fate
US /siːl ˈsʌm.wʌnz feɪt/
UK /siːl ˈsʌm.wʌnz feɪt/

1.
~の運命を決定づける, ~の破滅を確実にする
to make it certain that someone will fail or experience something unpleasant
:
•
His poor performance in the final exam sealed his fate for the scholarship.
期末試験での彼の成績不振が、奨学金に関する彼の運命を決定づけた。
•
The discovery of new evidence sealed the suspect's fate.
新たな証拠の発見が容疑者の運命を決定づけた。