Here's a clue: Love the lass you wish to bear your child. Make sure to your best ability that she loves you. Then marry her.
This works ninety-nine point nine percent of the time.
Actually it fails over 50% of the time so lets give the dads some support.
Your love scenario is good in theory though.
That advice is like the old Steve Martin joke:
"How to become a millionaire. First step, get a million dollars......"