Witness testimony is a key tool in criminal systems to uncover the truth and achieve justice. In the Iranian criminal system, testimony is based on religious requirements such as justice, reason, maturity and a certain number of witnesses and is rooted in Islamic jurisprudence. This system, by emphasizing honesty and transparency, seeks to reduce false testimony. Strict religious requirements increase the accuracy of the trial process, but may sometimes slow down the proceedings or create administrative complications. In contrast, the French criminal system has adopted a pragmatic approach that is based on the judge's free assessment and does not consider strict religious or moral requirements mandatory. This flexibility can speed up the proceedings, but it carries the risk of accepting unreliable testimony or the influence of external factors such as human error. Comparative analysis shows that the Iranian system, by focusing on religious requirements, reduces the possibility of errors in testimony, but may affect the efficiency of the process due to complex requirements. In contrast, the French system, by facilitating the acceptance of testimony, enhances efficiency, but carries the risk of reducing accuracy. This research suggests that a balanced combination of the Islamic rigor of the Iranian system and the flexibility of the French system can help improve the trial process. Such a combination can increase the efficiency and speed of proceedings while maintaining honesty and transparency and help achieve criminal justice.