" I need to know how you can be so certain,' Daniel said, his voice dropping into a furious hush.
'Well...' Hugh brought his glass to his lips and took something deeper than a sip. 'If you must know, I told him that if anything happens to you, I would kill myself.'
If Daniel had been holding anything, anything at all, it would have crashed to the ground. It was a remarkable thing that *he* did not crash to the ground.
'My father knows me well enough to know that I do not say such a thing lightly,' Hugh said, lightly.
Daniel couldn't speak.
'So if you would...' Hugh took another drink, this time barely touching his lips to the liquid. 'I would appreciate if you would endeavor not to get yourself killed in an unhappy accident. I'm sure to blame it on my father, and honestly, I'd rather not see myself off unnecessarily.'
'You're mad,' Daniel whispered ... 'Why would you do such a thing?' Daniel could not imagine anyone else - not even Marcus, who was truly a brother to him - making the same sort of threat. "

― Julia Quinn , A Night Like This (Smythe-Smith Quartet, #2)