idiom
Cross the Rubicon
後戻りできない決断をする、または戻れない一歩を踏み出す。
Meaning
To make an irreversible decision or take a step from which there is no turning back.
Example
By quitting his job, he **crossed the Rubicon** and committed to his startup dream.
仕事を辞めて、彼はルビコン川を渡り、スタートアップの夢に全力を注いだ。