How do you natives say the following sentence; I guess it should be said in another way, but I do not know how:
We are proud to announce our readiness for manufacturing any type of toys.
PS: I need to write this sentence at the end of a very official letter.
“We are proud to announce our readiness for manufacturing” is an awkward phrase for a couple of reasons; it’s long-winded, and appends a lot of two-word phrases to each other (“to announce,” “our readiness,” “for manufacturing”) which can be awkward to say.
Also, as @Jim pointed out below, you had a minor grammatical error at the end; “any” is to be used with a singular noun, so “toys” should be “toy.”
One possible way to re-write this sentence would be like this:
We are proud to announce that we are ready to manufacture any type of toy.
This separates the sentence into two very distinct clauses separated by the word “that” instead of a run-on of two-word phrases, which is much more agreeable to a native speaker like myself. However, you said the letter was official, and “ready” sounds a bit informal to me. I might end up writing the sentence like this, if I were writing the letter:
We are proud to announce that we are prepared to manufacture any type of toy.
Prepared can be used as a synonym for “ready” and connotes a much more formal style.