This problem field is as old as mankind, and - alas - no generally applicable solution has been found.
Your judgement can always be clouded by infatuation or disproportionate scrupulosity.
There is no way to make a fully objective decision as a human being on such matters.
Just use good judgement and hope and pray for the best.
A frequently overlooked insight is that the main point of marriage is not to make oneself happy.