Violet have you found girls more difficult than boys?
As you know I prayed for my girl for many years following five sons and ended up with two daughters, but I find them so much more emotionally demanding.
With boys what you see is what you get but girls, phew, how complicated are they !!!
As for the adult daughter and grandchild,
I think if it were me, I would prayerfully ask the Lord to open her heart, and then very carefully and gently explain why you feel the way you do, or as some have said, live it, make a conscious effort to live what you believe, I think there is a presidence for this in scripture, doesnt Timothy mention his Gran's instruction to him as a child?
Praying for you.