I don't know whether to go or stay.

Used to introduce choices or alternatives.
I can't decide whether to eat pizza or pasta.
She asked whether we should leave now or later.
He wondered whether it would rain today or tomorrow.
whether or not
whether to choose
whether to go
if
whether or not
in case
I don't know whether to go or stay.

Used to introduce alternatives or choices.
She asked whether it was going to rain.
I can't decide whether to eat pizza or pasta.
He wondered whether she would join us.
whether or not
whether to
whether it is
if
whether or not
in case
She asked whether I wanted tea or coffee.

Refers to a choice between two or more options.
I can't decide whether to go out or stay in.
He wondered whether she would join him for dinner.
They need to know whether we are coming or not.
whether or not
whether to choose
whether to go
if
either
which
The whether of his decision made her anxious.

The state of being uncertain between choices.
Her whether about moving made her hesitate.
He felt a sense of whether when choosing a career.
The whether of their plans left them feeling confused.
in a whether
whether or not
expressing whether
indecision
doubt
uncertainty