grateful
He remains eternally grateful to the teacher whose advice changed his life.
She says that she is eternally grateful for the support she has received from the people of Ireland.
We should all be eternally grateful to the extraordinary men and women who have worked so hard to make this happen.

SMART Vocabulary: related words and phrases

Relieved and thankful
all's well that ends wellidiom
appreciate
appreciative
appreciative of something
appreciatively
beholden
bless you!idiom
count
gratitude journal
I owe you (one)idiom
in acknowledgment of something
in debt to someone/something
indebtedness
mind
release
thank God, goodness, heaven(s), etc.idiom
thank your lucky starsidiom
thankful
thankfully
thankfulness