Saying
Ya Rasulullah, how can I not be pleased that you are interested in me, but there are three things you should know: I am a woman that has ghayra (jealousy) and you are a man that already has wives: I am worried that jealousy will act up and displease you, which will then displease Allah. I am a woman coming on in my age and I am not young. And I am a woman that has family: four children.
Saying
As for your ghayra, I will make du'a to Allah SWT, and insha'Allah it will be removed from your heart. As for your age, I am afflicted with the same calamity as you. And as for your family, they are my family.