Lew, my husband always says you have to train both sides of a horse. Just because they respond well to a stimulus on the left doesn't mean they will on the right side. And every person has two sides to their lives and personalities; the outside public image and who they are at home or in their private life. The problem is that we have to live and work with both sides but the inside person may be hard to discern in the short term.
This is very important when going into business partnership or a marriage relationship. A person might be a great salesperson and you think they will really build the business but they may be a gambler or someone who spends lots of money on unnecessary things so that the expenditures become far more than the income leading the partnership to bankruptcy. The funny, romantic boyfriend may be a real grouch or worse when the wife disrupts his private time or boy's play time.
So how on earth can we figure this out before we are caught in a web of disaster? I recommend you ask lots of questions to the person and everyone who already lives and works around them. Ask other bosses and co-workers if they find the potential business partner to be loyal, consistent, faithful, frugal, attentive to job details and thorough in completing a job for starters. Find out how many jobs they've had, how long they worked at each and why they left. The person may not be fully honest with you but asking people who don't like them as well as those that do why they do or don't can reveal a lot of truth. In buying a product my husband goes to each brand salesman and asks them what's wrong with the competition. You have to shovel through some muck that way but the truth actually becomes clear as to which brand is most valuable and dependable.
Choosing a life partner should also be investigated as carefully. First observe how thy treat parents, siblings and bosses. This will show if they are a GIVER or a TAKER. You may think you can help or rescue a TAKER but instead you'll find yourself completely used up in a short time. Next take siblings aside and ask what kind of brother or sister they are to their siblings. What does the sibling like about them and what do they dislike and why. Look at the parent of the same sex as your potential partner. Would you want to be married to them? Remember your potential spouse has psychologically imprinted on their example. That's one reason we have so many generations of divorced marriages. Also find out what really tough times this person has lived through and whether they have learned well and come out a better person from the tough time. Life gives us tough times and you want a partner who will stick it out and come through it with you. There, of course, is much more you could look into but this will get you started. Romantic love doesn't last long but a trustworthy dependable giving person is well worth a long term loving relationship. So enjoy the glamorous outside but check out the inside because you'll live with that side much longer.