Can a Christian Pretend to Denounce His Faith to Save His Life?

Questions about whether pretending to denounce your faith to save your life will cause you to lose your salvation, whether lying to save others’ lives is comparable to lying about your faith to save yourself, and advice for someone struggling with crippling intellectual doubts. Can a Christian pretend to denounce his faith to save his life so that he can continue to live his life for God, or will he lose his salvation? If lying to save others’ lives is acceptable, is denying your faith to save yourself or your family acceptable when you don’t mean it? Do you have any advice for someone struggling with crippling intellectual doubts?