Varun's main weakness in this interview was his inability to communicate clearly in English, as evidenced by his initial responses. This fundamental issue prevented him from effectively discussing his qualifications and how they relate to the role. Additionally, his responses did not address the questions directly, which could be improved with specific preparation focused on aligning his extensive experience with the job's requirements. Practicing clear, relevant responses and improving language proficiency would be crucial for Varun to succeed in future interviews.