I recommend telling the client you are married or have a girlfriend/boyfriend. It is not good to mix business with pleasure. It is also very unprofessional in my opinion. The last thing any business owner wants is unrealistic expectations of love effecting the job they are doing.
My business partner and I have had this happen to both of us recently. I am very clear that I have a wife! and a happy marriage! On one occasion I even brought her to the project site I was finishing.
Just stay polite and let them know you’re taken.
If you are single, its still not a good idea; remain professional.
Your License, Bond and Insurance counts on it!
ALWAYS be professional.
Be professional, minor innocent flirting is never a bad thing as long as it doesn’t cross a line.
Sometimes this can happen. If both of you are single, work this thing out after the job. I believe you should keep your mind on your work. Let them know that you were flattered with their wonderful comments but as a contractor I must complete this work for you. Do the best to keep your work in front of you and put all diversions to the side or on the back burner. Sometimes to protect yourself, you need a tape recorder running in your pocket.