Give her a choice. Pick three cars instead of one. Get pretty brochures from the dealers. Let her enjoy the gameshow aspect of it. She can choose the color, the car etc... She will likely end up picking the same car you would have chosen for her, but the act of choosing is its own reward as well. Mothers generally like to be 'advised and asked' much more than they like to be 'given or told' what to do.
