diff --git a/CHANGELOG b/CHANGELOG
index 065207b..480e18e 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -4,10 +4,8 @@ CHANGELOG
 0.5.1
 -----
 
-* Bump mockito-core from 2.21.0 to 2.22.0 (#36)
-* Bump mon from 0.12.0 to 1.1.0 (#38)
-* Bump mockito-core from 2.22.0 to 2.23.0 (#40)
-* Bump mon from 1.1.0 to 1.2.0 (#41)
+* Bump mon from 0.12.0 to 2.0.0 (#38)(#41)(#43)
+* Bump mockito-core from 2.21.0 to 2.23.0 (#36)(#40)
 * Bump kemitix-parent from 5.1.1 to 5.2.0 (#39)
 
 0.5.0
diff --git a/pom.xml b/pom.xml
index e063470..f9dd896 100644
--- a/pom.xml
+++ b/pom.xml
@@ -49,7 +49,7 @@
         <jacoco-class-line-covered-ratio>0</jacoco-class-line-covered-ratio>
         <jacoco-class-instruction-covered-ratio>0</jacoco-class-instruction-covered-ratio>
         <jacoco-class-missed-count-maximum>1</jacoco-class-missed-count-maximum>
-        <mon.version>1.2.0</mon.version>
+        <mon.version>2.0.0</mon.version>
     </properties>
 
     <dependencies>
diff --git a/src/main/java/net/kemitix/wiser/assertions/WiserAssertions.java b/src/main/java/net/kemitix/wiser/assertions/WiserAssertions.java
index 294b436..58060b4 100644
--- a/src/main/java/net/kemitix/wiser/assertions/WiserAssertions.java
+++ b/src/main/java/net/kemitix/wiser/assertions/WiserAssertions.java
@@ -22,6 +22,7 @@
 package net.kemitix.wiser.assertions;
 
 import net.kemitix.mon.maybe.Maybe;
+import net.kemitix.mon.result.Result;
 import org.subethamail.wiser.Wiser;
 import org.subethamail.wiser.WiserMessage;
 
@@ -31,7 +32,10 @@ import java.util.List;
 import java.util.Optional;
 import java.util.function.Predicate;
 import java.util.function.Supplier;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
 
+import javax.mail.BodyPart;
 import javax.mail.MessagingException;
 import javax.mail.internet.MimeMessage;
 import javax.mail.internet.MimeMultipart;
@@ -234,11 +238,7 @@ public final class WiserAssertions {
 
     private Maybe<String> contentAsMultiPartMime(final Object content) {
         if (content instanceof MimeMultipart) {
-            try {
-                return Maybe.just(getMimeMultipartAsString((MimeMultipart) content));
-            } catch (MessagingException | IOException e) {
-                throw new RuntimeException(e);
-            }
+            return mimeMultipartAsString((MimeMultipart) content);
         }
         return Maybe.nothing();
     }
@@ -264,22 +264,39 @@ public final class WiserAssertions {
      * @param mimeMultipart the message part to convert
      *
      * @return the message part as a string
-     *
-     * @throws MessagingException if the part is empty
-     * @throws IOException        if there is another error
      */
-    private String getMimeMultipartAsString(final MimeMultipart mimeMultipart)
-            throws MessagingException, IOException {
-        final StringBuilder sb = new StringBuilder();
-        for (int i = 0; i < mimeMultipart.getCount(); i++) {
-            Object content = mimeMultipart.getBodyPart(i).getContent();
-            if (content instanceof MimeMultipart) {
-                sb.append(getMimeMultipartAsString((MimeMultipart) content));
-            } else {
-                sb.append(content);
-            }
+    private Maybe<String> mimeMultipartAsString(final MimeMultipart mimeMultipart) {
+        return Result.toMaybe(Result.of(mimeMultipart::getCount)
+                        .map(count -> bodyPartsAsString(mimeMultipart, count)));
+    }
+
+    private String bodyPartsAsString(final MimeMultipart mimeMultipart, final int count) {
+        return IntStream.range(0, count)
+                .mapToObj(i -> bodyPart(mimeMultipart, i))
+                .map(this::bodyPartAsString)
+                .map(Result::orElseThrowUnchecked)
+                .collect(Collectors.joining());
+    }
+
+    private Result<String> bodyPartAsString(final Result<BodyPart> bodyPart) {
+        return bodyPartContent(bodyPart)
+                .flatMap(this::contentObjectAsString);
+    }
+
+    private Result<Object> bodyPartContent(final Result<BodyPart> bodyPart) {
+        return bodyPart.flatMap(part -> Result.of(part::getContent));
+    }
+
+    private Result<BodyPart> bodyPart(final MimeMultipart mimeMultipart, final int i) {
+        return Result.of(() -> mimeMultipart.getBodyPart(i));
+    }
+
+    private Result<String> contentObjectAsString(final Object content) {
+        if (content instanceof MimeMultipart) {
+            return Result.of(() -> mimeMultipartAsString((MimeMultipart) content).orElse(""));
+        } else {
+            return Result.ok((String) content);
         }
-        return sb.toString();
     }
 
 }