diff --git a/src/functions.rs b/src/functions.rs
index 2b002e2..8611a6a 100644
--- a/src/functions.rs
+++ b/src/functions.rs
@@ -871,10 +871,7 @@ fn container_to_string(value: &[u8], offset: &mut usize, json: &mut String) {
                 let jentry_encoded = read_u32(value, jentry_offset).unwrap();
                 let jentry = JEntry::decode_jentry(jentry_encoded);
                 let key_length = jentry.length as usize;
-                let key = unsafe {
-                    std::str::from_utf8_unchecked(&value[key_offset..key_offset + key_length])
-                };
-                keys.push_back(key);
+                keys.push_back((key_offset, key_offset + key_length));
                 jentry_offset += 4;
                 key_offset += key_length;
             }
@@ -883,8 +880,8 @@ fn container_to_string(value: &[u8], offset: &mut usize, json: &mut String) {
                 if i > 0 {
                     json.push(',');
                 }
-                let key = keys.pop_front().unwrap();
-                json.extend(format!("{:?}", key).chars());
+                let (key_start, key_end) = keys.pop_front().unwrap();
+                escape_scalar_string(value, key_start, key_end, json);
                 json.push(':');
                 scalar_to_string(value, &mut jentry_offset, &mut value_offset, json);
             }
@@ -912,10 +909,7 @@ fn scalar_to_string(
             json.push_str(&format!("{num}"));
         }
         STRING_TAG => {
-            let val = unsafe {
-                std::str::from_utf8_unchecked(&value[*value_offset..*value_offset + length])
-            };
-            json.extend(format!("{:?}", val).chars());
+            escape_scalar_string(value, *value_offset, *value_offset + length, json);
         }
         CONTAINER_TAG => {
             container_to_string(value, value_offset, json);
@@ -926,6 +920,38 @@ fn scalar_to_string(
     *value_offset += length;
 }
 
+fn escape_scalar_string(value: &[u8], start: usize, end: usize, json: &mut String) {
+    json.push('\"');
+    let mut last_start = start;
+    for i in start..end {
+        // add backslash for escaped characters.
+        let c = match value[i] {
+            0x5C => "\\\\",
+            0x22 => "\\\"",
+            0x2F => "\\/",
+            0x08 => "\\b",
+            0x0C => "\\f",
+            0x0A => "\\n",
+            0x0D => "\\r",
+            0x09 => "\\t",
+            _ => {
+                continue;
+            }
+        };
+        if i > last_start {
+            let val = unsafe { std::str::from_utf8_unchecked(&value[last_start..i]) };
+            json.push_str(val);
+        }
+        json.push_str(c);
+        last_start = i + 1;
+    }
+    if last_start < end {
+        let val = unsafe { std::str::from_utf8_unchecked(&value[last_start..end]) };
+        json.push_str(val);
+    }
+    json.push('\"');
+}
+
 // Check whether the value is `JSONB` format,
 // for compatibility with previous `JSON` string.
 fn is_jsonb(value: &[u8]) -> bool {
diff --git a/src/util.rs b/src/util.rs
index 03ce12a..e47150c 100644
--- a/src/util.rs
+++ b/src/util.rs
@@ -65,7 +65,10 @@ pub fn parse_escaped_string<'a>(
                 data = &data[1..];
                 data.read_exact(numbers.as_mut_slice())?;
                 if data[0] != b'}' {
-                    return Err(Error::Syntax(ParseErrorCode::UnexpectedEndOfHexEscape, *idx));
+                    return Err(Error::Syntax(
+                        ParseErrorCode::UnexpectedEndOfHexEscape,
+                        *idx,
+                    ));
                 }
                 data = &data[1..];
                 *idx += 6;
@@ -102,7 +105,10 @@ pub fn parse_escaped_string<'a>(
                         data = &data[1..];
                         data.read_exact(lower_numbers.as_mut_slice())?;
                         if data[0] != b'}' {
-                            return Err(Error::Syntax(ParseErrorCode::UnexpectedEndOfHexEscape, *idx));
+                            return Err(Error::Syntax(
+                                ParseErrorCode::UnexpectedEndOfHexEscape,
+                                *idx,
+                            ));
                         }
                         data = &data[1..];
                         *idx += 6;
diff --git a/tests/it/functions.rs b/tests/it/functions.rs
index 63f4d57..f51f948 100644
--- a/tests/it/functions.rs
+++ b/tests/it/functions.rs
@@ -662,6 +662,8 @@ fn test_to_string() {
         (r#"123.4567"#, r#"123.4567"#),
         (r#""abcdef""#, r#""abcdef""#),
         (r#""ab\n\"\uD83D\uDC8E测试""#, r#""ab\n\"💎测试""#),
+        (r#""မြန်မာဘာသာ""#, r#""မြန်မာဘာသာ""#),
+        (r#""⚠️✅❌""#, r#""⚠️✅❌""#),
         (r#"[1,2,3,4]"#, r#"[1,2,3,4]"#),
         (
             r#"["a","b",true,false,[1,2,3],{"a":"b"}]"#,
@@ -675,7 +677,6 @@ fn test_to_string() {
     let mut buf: Vec<u8> = Vec::new();
     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, expect);
diff --git a/tests/it/parser.rs b/tests/it/parser.rs
index 07945a5..07555b8 100644
--- a/tests/it/parser.rs
+++ b/tests/it/parser.rs
@@ -310,10 +310,7 @@ fn test_parse_string() {
             r#""\"ab\"\uD803\uDC0B测试""#,
             Value::String(Cow::from("\"ab\"𐰋测试")),
         ),
-        (
-            r#""⚠\u{fe0f}""#,
-            Value::String(Cow::from("⚠\u{fe0f}")),
-        ),
+        (r#""⚠\u{fe0f}""#, Value::String(Cow::from("⚠\u{fe0f}"))),
     ]);
 }