Not sure what the criteria is but according to the survey results of one travel and food website named 'Big 7 Travel' it seems that the 'Filipino' accent is the sexiest accent in Asia and the 21st sexiest accent in the whole world. XDv
Source: https://bigseventravel.com/2019/04/top-50-sexiest-accents-in-the-world-2019/
A short description can be found in the above link about the Filipino accent:
Gentle and soft, the accents you’ll hear when in the Philippines are simply lovely.
The first time I landed on Manila and was surrounded by nothing but people speaking in Tagalog (I'm from Visayas and thus my mother tongue is Visayan), the very first thing I noticed was how gentle (and even slow speaking) Tagalog speakers was.
So in a way I do agree with the above description about the Filipino accent: 'Gentle and Soft', especially Tagalog speakers. However, I personally won't describe it as a 'sexy accent'.
As for the sexiest accent in the world, the 'Kiwi' (New Zealand) accent takes the top, described as 'outrageously charming' by the travel and food website Big 7 Travel.
South African takes the 2nd, with Irish, Italian and Australian for 3rd to 5th sexiest language in the world.