Я говорю, что весь этот мир - ничто, за исключением тебя, моя роза; в этом мире ты для меня всё.

English Translation

May I say that in this world there is nothing but you - my rose. In this world you are everything to me.

If you want to tone down the English translation a bit to something a bit more palatable, here is my simple translation. “May I say that in this world there is nothing but you - my rose. In this world you are everything to me.”