"爱一个人不需要理由,如果你知道你为什么爱她,将来的某天,这也许会成为你们分手的理由”怎样翻译成英文

there's no reason for love.but if you do have one,which might turn into the reason why you two break up in the future.
love needs no reason.but if you know why you love her,which might turn into the reason that you say-goodbye to each other in the future.
都行 自己选选看

Love do not need a reason, if you know why you love her, and the future one day, this may be your reasons for breaking up.
参考资料:http://www.***.com/ss/fy.htm

不知道怎么翻译但俺相信这句话

直接Google就可以了