When you concern yourself with others, you naturally develop a sense of self-confidence. To help others takes courage and inner strength.
(From His Holiness the Dalai Lama's tweet on July 8, 2013)
Cf. https://twitter.com/DalaiLama/status/354169881450651648
「あなたが他のことを気にかける時、自然と自信の感覚を成長させています。他を助けるには、勇気と内面の強さを必要とします。」 (超訳)
These sentences mean that self-confidence is cultivated by practice of compassion which also brings courage and inner strength. (My commentary)
「この文章は、勇気と内面の強さをももたらす思いやりの実践によって、自信が育まれることを意味します。」 (解説)