I am so confused with the whole motive... 
Uh so, the neglected 5th prince kidnapped our mc... he was confused? angry? over how different ML from him even though theyre raised the same way? So he kidnapped our MC to get a reality check (aka making sure both 5th prince and ML is a bad guy at the bone after all)? Wait no, he tried to kill the ML? Uhhh??? Why?
And is the guy at the end the ex fiancee...? Is this some ploy?????