Formal:
* अच्छा मित्र (achchha mitra) - This is the most direct translation and is suitable for formal situations.
Informal:
* अच्छा दोस्त (achchha dost) - This is a more casual way to say "good friend" and is suitable for friends and family.
* सच्चा दोस्त (sachcha dost) - This translates to "true friend" and implies a deep and loyal friendship.
* प्यारा दोस्त (pyaara dost) - This translates to "dear friend" and is a more affectionate way to address a friend.
You can also use the word मित्र (mitra) or दोस्त (dost) by themselves, as they both mean "friend" in Hindi.
For example:
* वह मेरा अच्छा मित्र है। (vah mera achchha mitra hai.) - He is my good friend.
* मेरा एक सच्चा दोस्त है। (mera ek sachcha dost hai.) - I have a true friend.
Ultimately, the best way to say "good friend" in Hindi depends on the specific situation and your relationship with the person.