You should be true to your friends.
Wrong translation. 忠実 is closer to:
- “be loyal to someone” – i.e. “You” are the servant of the “friends”, which doesn’t make sense in this context.
- “to comply with rules/traditions/realities”
You should replace 忠実 with 誠実（せいじつ）or 真摯（しんし）.