"してます."
She reflexively studied the encryption used inside. Not an anti-letter, not a number substitution, not a fence cipher, not...
All known encryption methods were used and she still found nothing.
She looked at him doubtfully, trying to find some clues in his expression, but found that he quickly turned his head to avoid her gaze, but she couldn't help but carefully peek at her actions. She looked down and saw his hand on his side holding the midline of his pants, trembling slightly and unnoticeably.
She had an idea and stared at him more intently. Seeing his awkward expression that became more and more uncomfortable due to her sudden intense gaze, she suddenly realized something in her heart.
She smiled, her lips opened and closed, "してます."
Your words are a mystery, but only I know the answer.
This is really the best, riddle.
He turned his head sharply and looked directly at her, with incredible ecstasy in his eyes.
Their hands were held together quietly.
Hold your hand and grow old together.
This is the code of my love for you.