I know you probably already have a stable supplier. I am looking for you because I want to cooperate with you. You can also consider us as your alternative supplier.
I know you may already have a stable supplier at the moment. I'm looking for you to collaborate with you, and you can also consider us as an alternative supplier for you
I know that you may have a stable supplier at present. I came to you because I want to cooperate with you, and you can also regard us as your supplier alternative.