"What to politely say when...
One formula to bear in mind is the opportunity to show enthusiasm answer.
a polite generality with
information that simply makes it clear you are not in any way desperate, with
enthusiasm and specific enthusiasm
"Thanks for asking Jane. As you know there are a huge number of contracts available at the moment due to the shortage of programmers. But you know that this is where I want to work because of Mrs Smith and the XYZ project."
If you think about it, those are exactly the three things you need to communicate.
That you're on the same team - this is precisely the function of politeness and conventionality in human verbal interchange
It is crystal clear that you are not in the slightest desperate or needful of the position, yet,
you are truly enthusiastic about the position.
When you have a particular thought or concern about an upcoming negotiation. Such as precisely the excellent question posed here. It's absolutely important to have in mind a clear, memorized if you will, response to that particular concern. Then, that concern is boxed off and minimized so you can think and react in an agile way to the rest of the coming discussion.
This is a basic of preparing for a negotiation or meeting. If you do have a particular concern (such as the one posed in this QA), specifically get a clear response in mind so as to remove that concern from play in your preparations!