The Common Rose (Pachliopta aristolochiae) is a pretty Swallowtail, with its reddish pink spots and abdomen. 
The predominantly black forewings are shaded with grey along the distal half.
The sexes are similar except for the rounder wing contours of the female. 
The female looks very similar to the Common Mormon (Papilio polytes) which has a black abdomen as opposed to the Common Rose's red abdomen.

This is the subspecies Pachliopta aristolochiae asteris found in Singapore.

Singapore Botanic Gardens, Singapore, 7 November 2022