Does Clare die in the mange claymore

Short answer, No.

No official media has presented to suggest so. The only available information is related to the events in the 18 vol. of the Manga. Where is Clare is consumed and assimilated by the Destroyer, a shapeless dark mass of intertwined bodies, emerges and spreads over an entire forest, sucking the life out of everything it touches.

In the confusion, Clare's lower torso is assimilated by the Destroyer, the upper torso dropping from Helen's , a fellow rouge Claymore, grip. The Destroyer lifts the remainder of Clare's body and assimilates her. Clare's will however takes control the yoki mass and seizes Priscilla, the central object of her revenge through the story, also allowing Deneve, another rouge claymore, and Helen to escape. Unable to kill Priscilla even then, The Destroyer and by extension Clare swallows the surrounding forest, finally contracting into a shapeless cocoon encapsulating both Clare, Priscilla and The Destroyer.

The Ghosts, the rouge Claymore's, bring the deformed cocoon to the outskirts of Rabona, a large populated town the Ghosts have held up in on their new campaign. Galatea, another rouge Claymore that is however not a Ghost, examines it and confirms the presence of Clare and Priscilla. Galatea warns that releasing Clare from the cocoon would likely free Priscilla.

So alive... yes but not necessarily living in the larger sense of things. Again no official material has made things any clearer or hinted any light to when/if Clare will ever emerge from her cocoon and even then by what form.