Méiyǒu rén xiǎng qù, zuìhòu tā zìgào fènyǒng chéngdān le xiàlái.
No one wanted to go, and in the end she volunteered to take it on.
Tips
usage
自告奋勇 always describes someone proactively stepping up without being asked, often implying courage or initiative. It cannot be used when someone is nominated by others.