One of my fellow Dialog in Deutsch participants works as a live-in carer for an elderly woman with dementia. She is a Betreuerin. In a novel I was reading, one of the characters set up scams to get people, perhaps elderly and with dementia, to part with their money. She is a Betrügerin. While there is a vowel difference in the second syllable – /ˈtrɔy/ vs. /ˈtry:/ – this is rather subtle for the non-native ear, and thus that G becomes quite important to distinguish whether someone is being helpful or doing something harmful.
According to the Wortbildung analysis on canoo.net, betreuen is formed from the prefix be and the adjective treu – “faithful” or “true” – and betrügen is formed by adding be to the verb trügen – “to deceive” and gegenteil-von.com gives treu sein as the opposite of betrügen!
Earthquake Words/Erdbeben Wörter 