Formal:
* Nous aimons beaucoup notre petite-fille. (We love our granddaughter very much.)
* Nous adorons notre petite-fille. (We adore our granddaughter.)
Informal:
* On adore notre petite-fille! (We love our granddaughter!)
* On l'aime beaucoup, notre petite-fille! (We love her very much, our granddaughter!)
You can also use more affectionate terms like:
* Notre petite chérie (Our little darling)
* Notre petit cœur (Our little heart)
Here are some examples of how to use them in a sentence:
* Nous aimons beaucoup notre petite-fille, elle est si gentille. (We love our granddaughter very much, she is so nice.)
* On adore notre petite-fille, elle nous fait tellement rire! (We love our granddaughter, she makes us laugh so much!)
* Notre petite chérie, on t'aime beaucoup! (Our little darling, we love you very much!)
Remember to choose the phrase that best suits your situation and your relationship with your granddaughter.