Writing help pleezzz +10 points (answer mine and i will do the same for you)? ?

okay so im writing a story i already have a small twist there is a girl that gets in a car accident and her brother dies and she eventually falls for the guy that caused it. (btw this guy does a lot of street fighting for money) this guy is also very headstrong and violent much like her brother (which is one of the reasons she likes him so much, he reminds her of her brother.) Do u think it would be unbelievable 2 write that he gets a lil violent with her? Like grabbing her violently and smashing wholes in walls? Buy they still love each other? Do u think this is possible, or to unbelievable 2 write about? anyways i want there 2 be a BIG twist or surprise in the story. And i want there 2 be action and have there be maybe a little bit of a goose chase that they go on. So i need them to have a serious bad guy someone that is after them. but i have 2 make it believable. So maybe one of the guys he had fought with before or something. Anyways pllleeezzzz give me any crazy surprising twists you would like to read in a book, even if they don't have anything to do with what i was saying b for i would just like ur ideas. anyways i will answer yours if you answer mine, just leave a link :)