When Mrs. Travers says Maury has a sterling character, that he will be a "dear uncomplicated man," it's all to say that he will be like Mr. Travers.
It isn't until the end of the story that we see Mr. Travers in a slightly different, more dramatic light:
He was polite and businesslike, firm, cool, not unkind. (314)
Grace sees him in circumstances "that let him come into his own. A man who could take charge, who could tidy things up" (314).
With both Maury and Mr. Travers, it's possible to view their admirable qualities—soft-spoken, innocent, determined—as boring. They don't seem to have hidden depths. There appears to be no mystery. But the way Grace perceives Mr. Travers at the end of the story may suggest otherwise.