LAUSR

PurposeThe purpose of this study is to investigate the impact of the language style of certainty in social media influencers’ (SMIs) generated content on consumers’ purchase behavior. It aims to provide insights into how the use of certainty language style by SMIs influences consumers’ perceptions and subsequent purchase decisions in the context of influencer marketing.Design/methodology/approachThis research adopts a mixed-methods approach, combining a field study and a controlled experiment to examine the influence of language style of certainty in SMIs-generated content on consumers’ purchase behavior. The field study involved analysis of 17,920 SMIs-generated real short video content, while the controlled experiment allows for a systematic examination of the effects of certainty language style.FindingsThe findings of this study demonstrate that the use of certainty language style positively influences consumers’ perceptions of SMIs’ professional competence, leading to increased purchase behavior. Specifically, SMIs who employ the language style of certainty are perceived as more professional, which positively impacts consumers’ likelihood of making purchases. Furthermore, the influence of certainty language style is weaker when the content is labeled as sponsored, as consumers may perceive sponsored content as less authentic and more persuasive.Originality/valueThis research provides valuable insights into how SMIs can effectively craft content to promote purchase behavior on social media platforms. Additionally, this study highlights the moderating role of the sponsored label, extending our understanding of the interplay between certainty language style, professional competence perception, and consumers’ purchase behavior in the context of influencer marketing.