Are you being too kind to it so it grows leaves rather than flowering? Mine is on a north facing windowsill, gets watered when I think about it or notice its looking a bit sad, and only fed very occasionally. Its been in the same pot for years. And it flowers very regularly. So try a bit of meaness.

Hmm, well, what's commonly known as Peace Lily in the UK is Spathiphyllum - I note that Peace Lily appears to be used for other plants as well, but there is no such thing as a pink peace lily. The plant you have is most likely an anthurium with pink bracts, and these are not easy to get into flower again once they've stopped. They're quite picky about their conditions (unlike Spathiphyllum) - the need very bright light but not direct sunlight, hate to dry out but don't like to be waterlogged, should be fed with a liquid feed for flowering houseplants after 'resting' for a couple of months of non flowering, and temperature should never be less than about 58 - 60 deg F even at night. Repot in spring if necessary, splitting the plant every couple ofyears.