你永远也不懂我曾经多爱你
[nĭ yŏng yuăn yĕ bù dŏng wŏ céng jīng duō ài nĭ]
You never understand how much I once loved you'. Suggestive of regret or nostalgia. It describes someone who deeply regrets not getting their past feelings acknowledged properly or believes another couldn’t fathom those previous intense affections regardless of explanation.