Through a list experiment, this study points out the limitation of public opinion survey. Especially when it comes to the issue related to people’s willingness to fight in a war, interpreting the poll requires careful consideration of overestimation caused by “social desirability bias.” By combing an online survey and list experiments, this paper examines how social desirability bias impacts Taiwanese’s determination to fight. The results show that if China invades Taiwan by force, about 64% are willing to fight for Taiwan. By comparing direct and indirect questions, we estimate that at least 7% of the respondents tend to conceal their true preferences and give a “correct” answer that is generally accepted by society. Our multivariate analyses discover that people’s willingness to fight is affected by a combination of assessments of the capabilities of the R.O.C. armed forces, trust in the U.S. security commitment, and Taiwanese identity. Accordingly, strengthening Taiwan’s defense capabilities, maintaining cooperative relations with allies, and consolidating Taiwan consensus are the only ways to enhance Taiwanese’s defense awareness and determination to resist the enemy.