What does 'ella no es muy seria es bastante' mean?

The phrase "ella no es muy seria, es bastante" translates to "she is not very serious, she is quite" in English. However, it seems to be incomplete, as it lacks a concluding adjective or description after "bastante." This suggests that the speaker is indicating that while she may not be serious, there is a positive or defining quality that follows, which is missing from the phrase.