And to echo someone else's question, how did you decide the lady was not wife material?
Was it before or after landing?
Why date and sleep with someone you believe is not wife material? Isn't that deception?
People can learn on the job. If the lady is not an extreme case - like being a pharmacist, commercial airport etc. - marry her and both of you can learn on the job. Making someone pregnant and leaving her is not something to be taken lightly. You must have a VERY good reason. For starters, can you qualify "Not wife material"!
Never count on making a good sale. Have the purchase price be so attractive that even a mediocre sale gives good returns.