"Xuan'er, wait for me for two years. As long as it takes two years, I will take you back."
"Brother, I will wait for you, no matter how long it takes, I will wait for you."
They are brothers and sisters, and they love each other very deeply.
She secretly decided that even if he was her brother, she would love him no matter what.
He promised her two years, and he didn't care even if he gave up his country, as long as he could protect her.