Acting is a born talent (of varying degrees) that can be polished. The amount of polishing needed varies from person to person. The desire to act is NOT necessarily in proportion to the talent to act. The reasons people desire to act vary, falling loosely into these categories: desire for fame, for money, for glamour, for fulfillment, for self-expression, a love for the ART of acting, or because acting is a necessity like food and water. But the bottom line is that if you are born with a talent for acting, YOU CANNOT LOSE THAT TALENT.

If the desire to act is based on a love for the art and if that desire is accompanied by a bit of talent, then yes that love will indeed greatly compensate for minimum talent. It is my consistent contention that talent is never (or almost never) the main reason for a casting decision. We have dozens of famous stars who have almost no ability to act whatsoever. They are stars because of looks, personality, drive, ego, whatever. But stars they are!