Headcanon where Sasuke is the first one in the relationship that believed they were soulmates. When he had whispered the confession to Naruto, Naruto had laughed, thinking Sasuke was pulling his leg but when he looked into dark eyes and saw how sincere Sasuke was being, he shut his trap. Naruto fell into silence and tried to process it all because Uchiha Sasuke, out of all people, really? “It’s what I believe,” Sasuke explained calmly and Naruto flushed all shades of red. Then, taking Sasuke’s hand, Naruto squeezed it reassuringly and replied, “And I believe in you, so I believe we’re soulmates too.” The two broke into a smile, Sasuke’s gentle while Naruto’s was lopsided and they both leant forward to kiss their other half.