From Sahih Bukhari (Hadith 4325):
Narrated `Abdullah bin `Amr:When Allah's Messenger (ﷺ) besieged Taif and could not conquer its people, he said, "We will return (to Medina) If Allah wills." That distressed the Companions (of the Prophet (ﷺ) and they said, "Shall we go away without conquering it (i.e. the Fort of Taif)?" Once the Prophet (ﷺ) said, "Let us return." Then the Prophet said (to them), "Fight tomorrow." They fought and (many of them) got wounded, whereupon the Prophet (ﷺ) said, "We will return (to Medina) tomorrow if Allah wills." That delighted them, whereupon the Prophet (ﷺ) smiled. The sub-narrator, Sufyan said once, "(The Prophet) smiled
Reference: Bukhari 4325