Selling our commercial property – strategy

Hi Just looking for some collective strategies for selling our property.

I have a commercial property in a small town which the tenant has vacated.
I have approached the local agent also another agency is the next town because the operator is well connected with whats going on in the area.
Also another agent who is not local but seems to have the lions share of the available commercial properties for sale and lease in the area.

So the agents have got back to me with similiar agency fees 3% and have mentioned that they have someone who is interested and will purchase? upon giving them the agency agreement

now, I have been up this rocky road before where the “original purchaser” fades into dust,
What I am thinking is to get the “purchaser thru the agent to put an offer in writing therefore qualifying the purchaser and we could sign the agreement and bang SOLD.

the trouble with these small towns is that if you annoy someone it spreads like wild fire, I just dont want to get stuck with the wrong agent and possibly letting a purchaser walk.

Your thoughts please