Hi Margriet!
Consider SocialShopWave app which includes a suite of social apps, including Social Reviews app. You can easily collect reviews by sending review request email after X days after purchase, ask reviews right on your site and display them on your Homepage or any other wished page. Moreover, you can motivate buyers to share positive reviews on social media, it helps boost social traffic and increase your brand's visibility.
Here you can read more about our app: https://apps.shopify.com/socialshopwave
Let me know if you have any questions.