Take another look at the sentence:

Jean always nibbles around the pit of a cherry, just as if she were eating a peach, because she is vain about her smile, she doesn't want to chip a tooth on the hard center.

The blank space between want and to is completely correct. She doesn't want is a main clause. To chip a tooth on the hard center is an infinitive phrase. An infinitive phrase will begin with an infinitive like to chip. When you connect an infinitive phrase to the end of a main clause, you need no punctuation.

Go back to the sentence to try again.

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