YOU SAID:

The fastest car in the world is a car that goes really fast

INTO JAPANESE

世界最速の車は本当に速くなる車です。

BACK INTO ENGLISH

World's fastest car is going really fast.

INTO JAPANESE

世界最速の車は本当に速いんです。

BACK INTO ENGLISH

It is world's fastest car is really fast.

INTO JAPANESE

それは世界最速の車は本当に速い。

BACK INTO ENGLISH

It is the world's fastest cars really fast.

INTO JAPANESE

世界最速の車を本当に高速です。

BACK INTO ENGLISH

World's fastest car is really fast.

INTO JAPANESE

世界最速の車は本当に速いです。

BACK INTO ENGLISH

World's fastest car is really fast.