Umm Kulthum, the daughter of 'Uqba ibn Abi Mu'ayt, reported that she heard the Messenger of Allah, may Allah bless him and grant him peace, say, "Someone who makes peace between people by saying something good or relates something good is not a liar."  

أَنَّهَا سَمِعَتْ رَسُولَ اللهِ ﷺ يَقُولُ لَيْسَ الْكَذَّابُ الَّذِي يُصْلِحُ بَيْنَ النَّاسِ فَيَقُولُ خَيْرًا أَوْ يَنْمِي خَيْرًا قَالَتْ وَلَمْ أَسْمَعْهُ يُرَخِّصُ فِي شَيْءٍ مِمَّا يَقُولُ النَّاسُ مِنَ الْكَذِبِ إِلاَّ فِي ثَلاَثٍ الإِصْلاَحِ بَيْنَ النَّاسِ وَحَدِيثِ الرَّجُلِ امْرَأَتَهُ وَحَدِيثِ الْمَرْأَةِ زَوْجَهَا