情深似海抵不过他一言诋毁
[qíng shēn sì hăi dĭ bù guò tā yī yán dĭ huĭ]
'The depth of my affection is overwhelmed by one word of slander.' Despite deep feelings for someone, they find their efforts futile against even a single defamatory comment made by the other party. This shows immense disappointment caused by betrayal.