Kim Hee Sun confessed to Lee Min Ho using her sketchbook.
On October 9th, in the 18th episode of SBS's Monday-Tuesday drama 'Great Doctor', Eun Su (played by Kim Hee Sun) finds out that Choi Young (played by Lee Min Ho) is deeply saddened at the loss of his Woodalchi soldiers.
She told Choi Young, "Did you come here after not sleeping or eating? This is something I saw in a movie" as she grabbed the sketchbook she wrote on with a brush.
She wrote on the paper in Korean, "It's okay. I will stay by your side. Until That Day. Can I do That?" However, Eun Su read it to Choi Young differently. She said, "It's okay. Don't worry. Everything will work itself out. Right?" [Choi Young cannot read Korean because Korean had not been invented yet in the Goryeo era.]
At this, Choi Young smiled and said, "Point taken. Stay here and wait for me. I won't be late to take you to the heavenly door."