The Messenger of Allah ﷺ never laughed except with a smile.
ما كان ضحك رسول الله ﷺ إلا تبسما.
No references are available.
Tirmidhi narrated it in his Sunan (3642) and in Shamail (229) from Ahmad bin Khalid Khallal, who said, Yahya bin Ishaq told us, who said, Layth bin Saad told us, from Yazid bin Abu Habib, from Abdullah bin Harith bin Juz, who said, then he mentioned it.Its chain is hasan because of Yahya bin Ishaq Silhini, for his hadith is hasan. Tirmidhi said, sahih gharib.