Best portrait lens for the leica m e typ 220?

Here is what the site says about that.

From Leica M-E (Typ 220): Leica M-E (Typ 220): A rangefinder by Leica with a 18-megapixel full frame sensor, announced in 2012. A lower-priced M9 with the same 18-megapixel CCD sensor. Specs - Maker: Leica - Mount: Leica M - Sensor: Full frame, 36 x 24mm, crop factor 1.0 - Resolution: 18 megapixels - Stabilisation: none in the body; use stabilised lenses for slow shutter speeds - Announced: 2012 - Type: rangefinder Focal lengths on it Full frame is ...

From Portraits: Portraits: For portraits, the lens matters far more than the camera. A cheap body with a good portrait lens beats an expensive body with a kit zoom every time.

Quoted from this site's pages.