Meanings of invincibly cheerful in English

Though invincibly cheerful through it all, Aunt Tipping was always in trouble, if not for herself, for somebody else.

A very pleasant writer is Irving, a man of romantic and somewhat sentimental disposition, but sound of motive, careful of workmanship, invincibly cheerful of spirit.

It was invincibly cheerful, a toyland of white and pastel houses whose bright, uncurtained windows winked blandly through a dappling of green and yellow leaves.