Short, sweet, powerful.
Loved the concluding couplet. Tears/fears seems to be a commonly used rhyme, but it never loses its impact.
World/cold doesn't seem to rhyme in my head. >.>
But asides from that, it is very apt that the "never being free" is right in the middle of the poem, because it marks the transition from "what she shows" to what "really is." Also, I love characters were are strong on the outside and vulnerable on the inside. They always have this enigmatic depth to them. Makes them much more interesting that other types. Imho.
Also the couplet with "contained" and "feigned" awesome use of diction. You get both the "caged, trapped" feeling (possible caused by other people) as well as the element of "deception" on her part.