Daughter's fiance' to ask for her hand in marriage. How did you respond?

Yes, trust your daughter to make her own decisions about her life and have faith in the lessons and wisdom you have taught her.

Then support her decision and respect it.

All you can do it let her lead her own life...her way...and be there for her.

Any decision to include you in their plans shows respect for you and your wife as being important to them. Don’t let that respect be wasted, guide as you can, but never attempt to control.

They don’t need your permission to do what they want with their life...they are respectfully asking for it. And it shows they want you in their future.
With two daughters happily married I figured I was qualified to respond with some words of wisdom. Then I read Ddaddy response and thought to myself .... that about covers it, nothing else to add. His advice was spot on and well written. All I can say is I did it that way and am now blessed with grandkids and two great son in laws. There is literally nothing to add to his sage advice.