Personal Affair (Harlequin Presents, #447)
Flora Kidd

Stage glasses and a severe hairdo had tacked Gregory Lindley into thinking that Margret was right for the job of housekeeper-governess. Maybe it was because he never really looked at her.
Which was fine. Too bad Carl, Greg's rugged and impulsive cousin, wasn't as easy to outwit. He soon found out Margret's true age--and the story of her life!
But that didn't stop him from offering to whisk her off to Peru Margret knew better than to agree--but her heart was tempting her to go...