你的心是铁的连锈都不生
[nĭ de xīn shì tiĕ de lián xiù dōu bù shēng]
Translates literally to 'Your heart is made of iron which does not rust', conveying a profound hardness and unchanging coldness of the other person's heart. Suggests deep feelings being ignored without any sign of the other party changing their mind or growing affection over time.