Their time of courtship lasted only 4 months. 4 months filled with late night phone calls and shy attempts at talking to one another. Jaehee fancied the boy for quite some time, while Sehun wasn't necessarily looking for a relationship at the moment. All that changed when an occurence that needed the two to be forced together happened. The two naturally became friends and gradually feelings started to bloom. 

4 months. 4 months was all it took for Sehun to muster up all his courage and ask Jaehee to be his official girlfriend.