An interesting question. For the much of the poem, it seems odd to ask the question; the narrator is describing a woman. Since I don't know her, it would be hard to say if it is accurate or not. In general, though, I agree with it. People, and especially women, given our culture's emphasis on female beauty, can, at first glance be like a silk tent: lovely, precious, expensive to maintain, vulnerable. These people can, however, have both a strong central core reaching to heaven and a set of many lines (obligations) binding them to society. That rings true.