diff --git a/Userland/Libraries/LibJS/Runtime/Temporal/Instant.cpp b/Userland/Libraries/LibJS/Runtime/Temporal/Instant.cpp
index 32667e2bfe6..44c2e750b0e 100644
--- a/Userland/Libraries/LibJS/Runtime/Temporal/Instant.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Temporal/Instant.cpp
@@ -259,8 +259,8 @@ ThrowCompletionOr<DeprecatedString> temporal_instant_to_string(VM& vm, Instant&
     // 6. Let dateTime be ? BuiltinTimeZoneGetPlainDateTimeFor(outputTimeZone, instant, isoCalendar).
     auto* date_time = TRY(builtin_time_zone_get_plain_date_time_for(vm, output_time_zone, instant, *iso_calendar));
 
-    // 7. Let dateTimeString be ? TemporalDateTimeToString(dateTime.[[ISOYear]], dateTime.[[ISOMonth]], dateTime.[[ISODay]], dateTime.[[ISOHour]], dateTime.[[ISOMinute]], dateTime.[[ISOSecond]], dateTime.[[ISOMillisecond]], dateTime.[[ISOMicrosecond]], dateTime.[[ISONanosecond]], undefined, precision, "never").
-    auto date_time_string = TRY(temporal_date_time_to_string(vm, date_time->iso_year(), date_time->iso_month(), date_time->iso_day(), date_time->iso_hour(), date_time->iso_minute(), date_time->iso_second(), date_time->iso_millisecond(), date_time->iso_microsecond(), date_time->iso_nanosecond(), nullptr, precision, "never"sv));
+    // 7. Let dateTimeString be ! TemporalDateTimeToString(dateTime.[[ISOYear]], dateTime.[[ISOMonth]], dateTime.[[ISODay]], dateTime.[[ISOHour]], dateTime.[[ISOMinute]], dateTime.[[ISOSecond]], dateTime.[[ISOMillisecond]], dateTime.[[ISOMicrosecond]], dateTime.[[ISONanosecond]], undefined, precision, "never").
+    auto date_time_string = MUST(temporal_date_time_to_string(vm, date_time->iso_year(), date_time->iso_month(), date_time->iso_day(), date_time->iso_hour(), date_time->iso_minute(), date_time->iso_second(), date_time->iso_millisecond(), date_time->iso_microsecond(), date_time->iso_nanosecond(), nullptr, precision, "never"sv));
 
     DeprecatedString time_zone_string;
 
diff --git a/Userland/Libraries/LibJS/Runtime/Temporal/ZonedDateTime.cpp b/Userland/Libraries/LibJS/Runtime/Temporal/ZonedDateTime.cpp
index 6a7bd940677..11ffcb60eaf 100644
--- a/Userland/Libraries/LibJS/Runtime/Temporal/ZonedDateTime.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Temporal/ZonedDateTime.cpp
@@ -313,8 +313,8 @@ ThrowCompletionOr<DeprecatedString> temporal_zoned_date_time_to_string(VM& vm, Z
     // 8. Let temporalDateTime be ? BuiltinTimeZoneGetPlainDateTimeFor(timeZone, instant, isoCalendar).
     auto* temporal_date_time = TRY(builtin_time_zone_get_plain_date_time_for(vm, &time_zone, *instant, *iso_calendar));
 
-    // 9. Let dateTimeString be ? TemporalDateTimeToString(temporalDateTime.[[ISOYear]], temporalDateTime.[[ISOMonth]], temporalDateTime.[[ISODay]], temporalDateTime.[[ISOHour]], temporalDateTime.[[ISOMinute]], temporalDateTime.[[ISOSecond]], temporalDateTime.[[ISOMillisecond]], temporalDateTime.[[ISOMicrosecond]], temporalDateTime.[[ISONanosecond]], isoCalendar, precision, "never").
-    auto date_time_string = TRY(temporal_date_time_to_string(vm, temporal_date_time->iso_year(), temporal_date_time->iso_month(), temporal_date_time->iso_day(), temporal_date_time->iso_hour(), temporal_date_time->iso_minute(), temporal_date_time->iso_second(), temporal_date_time->iso_millisecond(), temporal_date_time->iso_microsecond(), temporal_date_time->iso_nanosecond(), iso_calendar, precision, "never"sv));
+    // 9. Let dateTimeString be ! TemporalDateTimeToString(temporalDateTime.[[ISOYear]], temporalDateTime.[[ISOMonth]], temporalDateTime.[[ISODay]], temporalDateTime.[[ISOHour]], temporalDateTime.[[ISOMinute]], temporalDateTime.[[ISOSecond]], temporalDateTime.[[ISOMillisecond]], temporalDateTime.[[ISOMicrosecond]], temporalDateTime.[[ISONanosecond]], isoCalendar, precision, "never").
+    auto date_time_string = MUST(temporal_date_time_to_string(vm, temporal_date_time->iso_year(), temporal_date_time->iso_month(), temporal_date_time->iso_day(), temporal_date_time->iso_hour(), temporal_date_time->iso_minute(), temporal_date_time->iso_second(), temporal_date_time->iso_millisecond(), temporal_date_time->iso_microsecond(), temporal_date_time->iso_nanosecond(), iso_calendar, precision, "never"sv));
 
     DeprecatedString offset_string;