When you’re in love, you’re happy. You see all the great things about your darling. Even things that might irritate you if other people did them are endearing when your honey does them. It’s just great. Finally you’ve found the one. And you think about taking it to the next level.

At the risk of being a downer, I suggest that you pause before you get engaged or move in together. Your heart may be right when it says this is the person for you—but you need to check with your brain, too. Remember the old saying: “Marry in haste, repent at leisure.”

That’s because being in love isn’t the only thing you’ll need for a satisfying life together. Rather than a passionate choice, make an informed decision. Passion is only one element of that decision.

Before you commit, you need to evaluate three things:

What are the ways we don’t fit well together? Even the happiest relationships have some areas that aren’t so great. Even the best people have some annoying habits, moods, insecurities, and quirks. Before you commit, you’ll want to know exactly what those are. What things, over time, are likely to be irritating? Where do your hobbies, activities, goals, and ideas not overlap? Where are you likely to have ongoing conflict? All of these may be manageable—but it’s essential that you know what they are.

How trustworthy is this person? Of course you want to give her the benefit of the doubt. Of course you take his side when you hear about problems earlier in his life. Being an ally to your partner is part of what makes a relationship work.

But: Not everyone is honest. Some people intentionally mislead, either by outright lying or by neglecting to mention crucial information. Others put such a spin on stories that they’re quite different from objective reality. If your partner isn’t being straight with you now, that’ll probably continue throughout your relationship—with painful and sometimes devastating consequences.

How can you tell if your honey is honest? Look for little things like cheating at a game, small fibs, failing to mention inconvenient facts, or praising people who’ve gotten away with dishonest behavior. In contrast, honest people will take a deep breath and tell you about things they regret, unflattering truths, or ways they’ve behaved badly in the past. They fess up—before you hear about the negative things from someone else.

What is his/her relationship with money? Especially if you’re considering getting married or having children together, the way your SO handles money will have a huge impact on your happiness. This person can ruin your credit rating. Even if you have millions, a spendthrift spouse could bring you to bankruptcy. If you’ve got an ordinary income, divergent spending styles will likely cause chronic conflict.

Pay attention: Does your honey buy things she can’t really afford? Does he treat you to nice things—without ever paying off the credit card? Does she talk about “deserving” indulgences—or about funding her 401(k)? What do you know about his financial history? If she has debts, are they from, say, student loans and buying a practical car, or from spending on a lifestyle that’s bigger than her income?

Before you make a commitment, have a candid conversation (or several) about how you’ll handle money together. How much savings and how much debt do each of you bring into the relationship? How much will you put in separate and joint accounts? How will you save for long-term goals? It’s not very romantic, but I’ve seen many marriages fail because they didn’t take financial styles seriously.

The keys: knowing the whole person and being realistic. It takes years to really know someone, and it’s hard to be objective when you’re madly in love. But taking the time to learn about your sweetie and to think about the realities of life together make it much more likely you’ll have a happily-ever-after.