倾国倾城的英文：
[Literal Meaning]
ruin/state/ruin/city
to be extremely beautiful as to overrun cities and ruin states

[解释]
倾：倒下来。女人美丽可以使国家灭亡，城陷落。形容女人非常美丽。

[Explanation]
(of a woman) extremely beautiful

[例子]
因为她有倾国倾城的容貌，两个国王甚至不惜为她发动战争。

[Example]
For her beauty which overthrows states and cities, the two kings would rather wage wars for her.

[英文等价词]
drop-dead gorgeous

His wife is an unmatched beauty.
他妻子是一个倾国倾城的美人。