ENOfficial
Abu `Ubaida b. Muhammad b. `Ammar b. Yasir told that he asked ar-Rubaiyi`, daughter of Mu'awwidh b. `Afra' to describe God's messenger to him, and she replied, "If you had seen him, sonny, you would have seen the sun rising." Darimi transmitted it.
Source: sunnah.com
Other translations
Arabic
وَعَنْ أَبِي عُبَيْدَةَ بْنِ مُحَمَّدِ بْنِ عَمَّارِ بْنِ يَاسِرٍ قَالَ: قُلْتُ لِلرُّبَيِّعِ بِنْتِ مُعَوِّذِ بْنِ عَفْرَاءَ: صِفِي لَنَا رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَتْ: يَا بُنَيَّ لَوْ رأيتَه رأيتَ الشَّمسَ طالعة. رَوَاهُ الدَّارمِيّ
sunnah.com