Including testimonials in emails can make your message more believable, especially when people are not sure about buying. A testimonial is simply a short review or feedback from a real customer who has used your product or service. When readers see proof from others, it builds confidence and trust. However, you should not overload your email with too many of them. One or two short, clear testimonials are enough. Make sure they sound genuine, not like something written by a marketing team. Have you noticed if real-life reviews make you pay more attention to a product?