To swallow something hook, line and sinker

To swallow something hook, line and sinker - to believe something completely.

Example - "I made up a story about why I was so late. The boss swallowed it hook, line and sinker."

Image -https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgatWnMFoR0G4dzJSfpRxVHa-6t-gXMavjTuHVCv_PCqlAgxpTb3LCfpnKtCY93JkUgKTScTIkKVvwn6lYwFOqOzh1jDN_f7AfAiDhaEj46STmvIsbPqsSWARv040niJCFiPOxY5_fr05RV/s1600/hook-line-and-sinker+(1).jpg