Here’s some copy you could use:

Hey [name] –

While I was working on your refi, I noticed another way you could save. If it’s okay with you, I’d like to share your information with Shine Insurance Agency. They’re a boutique insurance agency that offers great coverage and pricing.  Pretty sure they could help out and save you some money on insurance.

All good either way but will you reply yes or no to this email so I know if I should forward your contact info or not. I’ll get the ball rolling from there.

Here’s to you saving lots of dough!