diff --git a/src/de.rs b/src/de.rs
index 9500172..c51f77c 100644
--- a/src/de.rs
+++ b/src/de.rs
@@ -111,7 +111,7 @@ impl<'a> Decoder<'a> {
             FALSE_TAG => Ok(Value::Bool(false)),
             STRING_TAG => {
                 let offset = jentry.length as usize;
-                let s = std::str::from_utf8(&self.buf[..offset]).unwrap();
+                let s = unsafe { std::str::from_utf8_unchecked(&self.buf[..offset]) };
                 self.buf = &self.buf[offset..];
                 Ok(Value::String(Cow::Borrowed(s)))
             }
diff --git a/src/functions.rs b/src/functions.rs
index ff7113e..2b002e2 100644
--- a/src/functions.rs
+++ b/src/functions.rs
@@ -792,10 +792,16 @@ pub fn as_str(value: &[u8]) -> Option<Cow<'_, str>> {
 pub fn to_str(value: &[u8]) -> Result<String, Error> {
     if let Some(v) = as_str(value) {
         return Ok(v.to_string());
-    } else if is_null(value) {
-        return Err(Error::InvalidCast);
+    } else if let Some(v) = as_bool(value) {
+        if v {
+            return Ok("true".to_string());
+        } else {
+            return Ok("false".to_string());
+        }
+    } else if let Some(v) = as_number(value) {
+        return Ok(format!("{}", v));
     }
-    Ok(to_string(value))
+    Err(Error::InvalidCast)
 }
 
 /// Returns true if the `JSONB` is An Array. Returns false otherwise.
@@ -878,9 +884,7 @@ fn container_to_string(value: &[u8], offset: &mut usize, json: &mut String) {
                     json.push(',');
                 }
                 let key = keys.pop_front().unwrap();
-                json.push('\"');
-                json.push_str(key);
-                json.push('\"');
+                json.extend(format!("{:?}", key).chars());
                 json.push(':');
                 scalar_to_string(value, &mut jentry_offset, &mut value_offset, json);
             }
@@ -911,9 +915,7 @@ fn scalar_to_string(
             let val = unsafe {
                 std::str::from_utf8_unchecked(&value[*value_offset..*value_offset + length])
             };
-            json.push('\"');
-            json.push_str(val);
-            json.push('\"');
+            json.extend(format!("{:?}", val).chars());
         }
         CONTAINER_TAG => {
             container_to_string(value, value_offset, json);
diff --git a/src/value.rs b/src/value.rs
index b895be8..69959ef 100644
--- a/src/value.rs
+++ b/src/value.rs
@@ -69,9 +69,7 @@ impl<'a> Display for Value<'a> {
             }
             Value::Number(ref v) => write!(f, "{}", v),
             Value::String(ref v) => {
-                write!(f, "\"")?;
-                write!(f, "{v}")?;
-                write!(f, "\"")
+                write!(f, "{:?}", v)
             }
             Value::Array(ref vs) => {
                 let mut first = true;
diff --git a/tests/it/functions.rs b/tests/it/functions.rs
index af2ffed..63f4d57 100644
--- a/tests/it/functions.rs
+++ b/tests/it/functions.rs
@@ -654,26 +654,31 @@ fn test_to_type() {
 #[test]
 fn test_to_string() {
     let sources = vec![
-        r#"null"#,
-        r#"true"#,
-        r#"false"#,
-        r#"1234567"#,
-        r#"-1234567"#,
-        r#"123.4567"#,
-        r#""abcdef""#,
-        r#"[1,2,3,4]"#,
-        r#"["a","b",true,false,[1,2,3],{"a":"b"}]"#,
-        r#"{"k1":"v1","k2":[1,2,3],"k3":{"a":"b"}}"#,
+        (r#"null"#, r#"null"#),
+        (r#"true"#, r#"true"#),
+        (r#"false"#, r#"false"#),
+        (r#"1234567"#, r#"1234567"#),
+        (r#"-1234567"#, r#"-1234567"#),
+        (r#"123.4567"#, r#"123.4567"#),
+        (r#""abcdef""#, r#""abcdef""#),
+        (r#""ab\n\"\uD83D\uDC8E测试""#, r#""ab\n\"💎测试""#),
+        (r#"[1,2,3,4]"#, r#"[1,2,3,4]"#),
+        (
+            r#"["a","b",true,false,[1,2,3],{"a":"b"}]"#,
+            r#"["a","b",true,false,[1,2,3],{"a":"b"}]"#,
+        ),
+        (
+            r#"{"k1":"v1","k2":[1,2,3],"k3":{"a":"b"}}"#,
+            r#"{"k1":"v1","k2":[1,2,3],"k3":{"a":"b"}}"#,
+        ),
     ];
     let mut buf: Vec<u8> = Vec::new();
-    for s in sources {
-        let res = to_string(s.as_bytes());
-        assert_eq!(res, s.to_string());
-
+    for (s, expect) in sources {
         let value = parse_value(s.as_bytes()).unwrap();
+        assert_eq!(format!("{}", value), expect);
         value.write_to_vec(&mut buf);
         let res = to_string(&buf);
-        assert_eq!(res, s.to_string());
+        assert_eq!(res, expect);
         buf.clear();
     }
 }