I'm 'grateful' (to you) for this opportunity. = I'm 'grateful' to have this opportunity. = I'm 'grateful' that I have this opportunity.
expressing my 'gratefulness' [=(more commonly) 'gratitude'] for this opportunity
The college 'gratefully' [='thankfully'] acknowledges your donation.
(..) It spills all over my pants. I mean, just... a nightmare. Dude, you so need GPS. I mean, for real. Like I said, we couldn't be more grateful. Can't we just dump 'em here? What, then somebody finds them? Then what? People have seen us. (..)2008 TvShow: Breaking Bad Title: Cat's in the Bag... Season: 1 Episode 2