I think she would be happy to know that we still think about her often.
It would make her happy to know that we still talk about her.
日本語の通りに英語に訳すと不自然な言い方になるので、下のようにしてみました。
1) I think she would be happy to know that we still think about her often.
「私たちが彼女のことをよく考えていることを知ったら喜んでもらえるだろうね。」
2) It would make her happy to know that we still talk about her.
「私たちが彼女のことを今でも話しているのを知ったら喜ぶだろうね。」
She would be happy to know that...
It would make her happy to know that ...
で「…と知ったら彼女は喜ぶだろうね」という言い方です。
ご参考になれば幸いです！
日本 
