Even if title comes back with some sort of lien wouldn’t the seller use their proceeds to cover that cost? I would say use your own money and ride it out.
Are you attempting to create a system where you collect a deposit from your buyer that you keep regardless of if the title comes back clean?
If I’m reading your post correctly that’s bad business and sounds like a good way for your buyer to feel taken advantage of and refuse to work with you/ bad mouth you.
On the other hand if you mean just enough to cover the title search so it doesn’t come out of your pocket should the deal fall through, again I would call that bad business and advise against it. The buyers are your customers and having a good relationship with a hand full of big buyers will make you successful. Those repeat customers come from treating them well and ensuring they come out of the deal feeling good.
I agree with @Jonathan Holmes . What makes you like that title company? Even though you have a done a few deals with them, continue to shop around and see what others charge to get your rates lowered. Also ask if they do free preliminary title checks so you can get in front of the problem immediately and let the seller's know its going to take some work so you may need a discount. As far as a non refundable deposit from your buyer... Don't do that if the fault is not their own. If it is the seller's fault that the price doesn't work then get a reduction and explain why. I put clauses to get my deposit back if the fault is of the seller ex: title is not clean, inspection, etc.