至死不渝的爱刻骨铭心的情
[zhì sĭ bù yú de ài kè gú míng xīn de qíng]
These terms describe profound and unwavering love and deep, unforgettable affection. They are expressions reflecting commitment that transcends life ('to death') and feelings so strong they are etched in one’s heart (bone and marrow). These phrases highlight extremely intense and lifelong passion or dedication.