sister wants to steal her sisters husband (twice) (edit: make that 3), doctor of remarkable skill (not omnipotent though) meets crippled prince, attempted poisoning/wounding/crippling/murdering of characters, framings etc.
They get attacked by assassins on their wedding night just as Xiao Tianyao is threatening to kill her (for being a humiliating pawn in the Emperor's scheme), and instead of hiding and screaming for help or fainting, as one would expect a regular spoiled and sheltered girl to be, she walks around cool as a cucumber giving first aide to allies and enemies alike (allies who aren't actually her allies, since they are his men and he intended to kill her) and eventually uses a powder in self-defence that puts everyone to sleep (except Xiao Tianyao who has built a kind of immunity against poisons and sedatives).
She's aware she's being watched by his highly skilled secret guards despite not having any fighting ability herself, she apparently can predict when her room will be searched (he has her medical box stolen several times to try and see her strange tools up close, but the only thing in there is a note addressed to him every time, and the tools are nowhere to be found), and he knows there's a lie somewhere about her explanation on how she got her medical knowledge and tools but as he can't find a trace of the truth he can't disprove her either (her master was a kind but secretive man who never told her his name but saw how she was truly treated in the Lin household and decided to help her by sneaking into her courtyard at night to teach her his skills... really?). Again as readers we get to know how and why she does all this, but Xiao Tianyao literally doesn't have a clue.
amongst other things, he leaks information to the enemy country so that they will start a war to force the Emperor to return his military power
She interrupts the treatment of his legs by the divine doctor he's been looking for and has had thoroughly vetted since before he knew her, making his recovery even less likely