Search for “Kadhalukku Mariyadhai – Yen Enathu Idhayam Full Song.” Avoid remixes or remastered versions unless you prefer them.

You can also search for the song on music streaming platforms like Gaana, Hungama, or Saavn, and set it as your ringtone.

This is one of the most legal and hassle-free methods, though it’s technically a “caller tune” rather than a phone ringtone.