YOU SAID:

With a smirk I suddenly enter

INTO JAPANESE

にやにや笑いながら急に入る

BACK INTO ENGLISH

Enter suddenly with a grin

INTO JAPANESE

ニヤニヤしていきなり入る

BACK INTO ENGLISH

Grinning and suddenly entering

INTO JAPANESE

ニヤリと突然入って

BACK INTO ENGLISH

Grinning suddenly

INTO JAPANESE

いきなりニヤニヤ

BACK INTO ENGLISH

Suddenly grinning

INTO JAPANESE

いきなりニヤニヤ

BACK INTO ENGLISH

Suddenly grinning