Please imagine:
- A sales person / manufacturing company's directing manager ets. is marketing their recently produced goods or any other product in order to either be sold or be launched into the market via TV or in any meeting So it would not be surprising that they would make some good remarks for advertising them. Now, let's suppose that qualitatively the product is so poor or not all that they've made it out to be and you're well aware about it! As a saying you would probably say....................... [Sarcastically]
Or
- Let's suppose you are going to be hired in a company; you are sitting in front of the interviewer and talking to them now! The person asks you about your feedback about your character! You start to tell so many good things about you! The person just for fun would say........... [Humorously]
Figuratively, in both cases above, there is a saying in my language which literally says:
- No sales person make bad remarks about what they are supposed to sell!
In the course of my researches I bumped into several proverbs, which I have no any idea if they sound archaic; if they sound like translations from foreign proverb; if using them somehow would sound unidiomatic to a native person etc. I have listed them below:
1 - No fish-seller cries stinking fish.
2 - Every cook praises his own broth.
3- Every bird likes its own nest.
4- Every potter praises his own pot.
I would be grateful if you let me know which one is in current use in English, or if none of them works, what uaually a native speaker would say instead?