diff --git a/src/main/java/net/kemitix/wiser/assertions/WiserAssertions.java b/src/main/java/net/kemitix/wiser/assertions/WiserAssertions.java
index 07d0c56..920adc5 100644
--- a/src/main/java/net/kemitix/wiser/assertions/WiserAssertions.java
+++ b/src/main/java/net/kemitix/wiser/assertions/WiserAssertions.java
@@ -181,6 +181,9 @@ public final class WiserAssertions {
     private String getMimeMessageBody(final WiserMessage message)
             throws IOException, MessagingException {
         Object content = getMimeMessage(message).getContent();
+        if (content instanceof String) {
+            return (String) content;
+        }
         if (content instanceof MimeMessage) {
             return content.toString();
         }