YOU SAID:

there's a gun on my waist

INTO JAPANESE

私の腰に銃があります

BACK INTO ENGLISH

There is a gun at my waist

INTO JAPANESE

私の腰に銃がある

BACK INTO ENGLISH

My waist has a gun

INTO JAPANESE

私の腰は、銃を持っています。

BACK INTO ENGLISH

My waist has a gun.

INTO JAPANESE

私の腰は、銃を持っています。

BACK INTO ENGLISH

He's got a gun! - He's got a gun!

INTO JAPANESE

銃を持っています！

BACK INTO ENGLISH

He's got a gun! - He's got a gun!