I have a question concerning gusl.

We can do ONE ghusl for many niyyat right?

So, If someone have to make two wajib ghusl, and , after finishing his ghusl, she is not sure if he made the niyyat of the second gusl.
For example, I do one gusl for gusl hayz and janabat,
But after my gusl, I dont remember if I said the niyyat for jannabat.

So , my question is, when we do gusl, and we forget to say the niyyat, but , we are aware that we are making this gusl,
The ghusl still correct?

Yes you can do one ghusl with intention of different ones.

The intention does not need to be said aloud but one should know what they are doing ghusl for.