Definition
To completely believe a deception or falsehood; to be easily tricked or fooled.
完全上當
The scammer said he needed money to help a sick child, and she fell for it hook, line, and sinker.
騙子說他需要錢幫助一個生病的孩子，而她完全上當了。
He told me he was a billionaire, and I fell for it hook, line, and sinker, how foolish of me.
他告訴我他是億萬富翁，而我完全相信了，我多麼愚蠢啊。
She swore she hadn't stolen my wallet, and I fell for it hook, line, and sinker.
她發誓她沒有偷我的錢包，而我完全相信了。