He's fallen head over heels in love with his boss.

他深深迷恋上了他的上司。

《牛津词典》

They are head over heels in love.

他们是真心相爱。

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John is head over heels in love with Mary.

约翰真心地爱上了玛丽。

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With its charming accommodations and tantalizing perks, this week's escape might just send you head over heels in love.

BBC: Daily deal: Two nights in the Outer Banks

The RX100 spent most of that time in the hands of my girlfriend, who, I must add, is also head over heels in love with that thing.

ENGADGET: IRL: Sony's Cyber-shot DSC-RX100 and the full-frame RX1

Of course, there's a lot to be grateful for in my situation -- not the least of which is that I have a delightful daughter who I've fallen head over heels in love with myself.

CNN: I'm jealous of my baby -- a Mother's Day confession