diff --git a/go.mod b/go.mod
index 5e163f3..690236f 100644
--- a/go.mod
+++ b/go.mod
@@ -4,6 +4,6 @@ go 1.20
 
 require golang.org/x/text v0.9.0
 
-require github.com/morikuni/failure/v2 v2.0.0-20240407145138-d0020a5003d2
+require github.com/morikuni/failure/v2 v2.0.0-20240419002657-2551069d1c86
 
 require golang.org/x/exp v0.0.0-20230522175609-2e198f4a06a1 // indirect
diff --git a/go.sum b/go.sum
index 190c7fd..975bbe7 100644
--- a/go.sum
+++ b/go.sum
@@ -2,6 +2,8 @@ github.com/morikuni/failure/v2 v2.0.0-20230512003104-6bb497ead261 h1:Rqq1Kh/HMFt
 github.com/morikuni/failure/v2 v2.0.0-20230512003104-6bb497ead261/go.mod h1:tHod902kOvu2+09OAbzPMrE4B8fIc+M/2kl/UI3mDQI=
 github.com/morikuni/failure/v2 v2.0.0-20240407145138-d0020a5003d2 h1:TAkI7cXmMnSuuVs1J7Xm9+vGaw649eEVUTz193HyZS4=
 github.com/morikuni/failure/v2 v2.0.0-20240407145138-d0020a5003d2/go.mod h1:tHod902kOvu2+09OAbzPMrE4B8fIc+M/2kl/UI3mDQI=
+github.com/morikuni/failure/v2 v2.0.0-20240419002657-2551069d1c86 h1:f3IP/QdKL5cQe8fTFRWV0slL60Ss/goB2UntNcnOGqk=
+github.com/morikuni/failure/v2 v2.0.0-20240419002657-2551069d1c86/go.mod h1:tHod902kOvu2+09OAbzPMrE4B8fIc+M/2kl/UI3mDQI=
 golang.org/x/exp v0.0.0-20230522175609-2e198f4a06a1 h1:k/i9J1pBpvlfR+9QsetwPyERsqu1GIbi967PQMq3Ivc=
 golang.org/x/exp v0.0.0-20230522175609-2e198f4a06a1/go.mod h1:V1LtkGg67GoY2N1AnLN78QLrzxkLyJw7RJb1gzOOz9w=
 golang.org/x/text v0.9.0 h1:2sjJmO8cDvYveuX97RDLsxlyUxLl+GHoLxBiRdHllBE=
diff --git a/mlang.go b/mlang.go
index ee505e7..9cce58c 100644
--- a/mlang.go
+++ b/mlang.go
@@ -88,7 +88,7 @@ func (d Dict[M]) LogValue() slog.Value {
 
 // MarshalJSON implements json.Marshaler.
 func (d Dict[M]) MarshalJSON() ([]byte, error) {
-	return []byte(`"` + d.String() + `"`), nil
+	return json.Marshal(d.String())
 }
 
 func (d Dict[M]) String() string {
diff --git a/mlang_test.go b/mlang_test.go
index 0293bb9..1071aea 100644
--- a/mlang_test.go
+++ b/mlang_test.go
@@ -62,7 +62,7 @@ func TestSetDefaultLanguage(t *testing.T) {
 func TestDict_MarshalJSON(t *testing.T) {
 	hello := func(name string) mlang.Message {
 		return mlang.Dict[string]{
-			language.English: fmt.Sprintf("Hello, %s!", name),
+			language.English: fmt.Sprintf(`Hello, "%s"!`, name),
 			language.French:  fmt.Sprintf("Bonjour, %s!", name),
 		}
 	}
@@ -72,7 +72,7 @@ func TestDict_MarshalJSON(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	equal(t, string(bs), `"Hello, Alice!"`)
+	equal(t, string(bs), `"Hello, \"Alice\"!"`)
 }
 
 func equal(t *testing.T, got, want any) {