heartily

ad. 衷心地,真实地,热心地

I am heartily grateful to your help.

我衷心地感激你的帮助。

Tell him you Aunt Celeste heartily approves and wishes you both happiness forever.

请转告他，Celeste姑妈完全赞成这门婚事，并衷心地祝福你们永远幸福。