There's a difference to a Siren and a Mermaid. Many people say they are the same thing, but this is not true.
Mermaids are seductive and almost always end up with their true loves, for its the rule of the Fairy Tale Goddess.
Sirens seduce humans and draw them into the water where they kiss them to trade their souls to become human while the victim becomes a poor siren, miserable and cold, waiting for their chance to become human again. In some cases, sirens can be kind, but even if they are kind, they still have a hateful lust to be human and won't hesitate to become one.
Sometimes, very rarely, sirens will find love, but until then the mermaids and sirens have been at a quarrel.

We would know because we are them.