Shared hobbies are cheap. Shared values show up on Tuesday.

Quick answer: Interests tell you what she enjoys. Values tell you what she does when it costs her something. Watch her on the inconvenient days, and ask questions that force a choice instead of questions that invite a nice answer.

You've been out four times. She likes the same trails you do, quotes the same movies, and orders the hot sauce before she tastes the food. You're sure.

Then her friend cancels on her at the last minute, and she spends twenty minutes tearing that friend apart. Or she mentions, laughing, that she told her boss she was sick so she could go to a concert. Or her mother calls and she lets it ring, twice, and says "she can wait."

Maybe none of that matters. Maybe all of it does. You can't tell yet, because up to now you've mostly been comparing playlists.

Why interests fool you

Shared interests are the easiest thing in dating to find and the most pleasant to feel. They give you something to talk about, a reason to see each other again, and the warm sense that this person gets you.

They also cost nothing. Nobody has ever been tested by a mutual love of barbecue.

A marriage runs on different material: who gets up with the sick kid, what you do when money's tight, how you each treat your parents when they're old and difficult, whether a promise made in April still holds in October. Two people can share every hobby on earth and want opposite answers to all of those.

The reverse happens too. A woman who's never fired a gun or cast a line might share your convictions on loyalty, work, children and honesty down to the ground. You'd miss her entirely if you were screening by hobby.

Watch what it costs her

Values are invisible until they're expensive. So you're looking for moments with a price tag. A few places they turn up:

Small people. How does she treat the waiter, the teenager at the register, the guy who cut her off in traffic? Somebody who's gracious only toward people who can do something for her is showing you a transaction, not a character. You're a person who can do something for her right now. Remember that.

Her word. Does she show up when she said she would? Does she text if she's running late, or just appear forty minutes in with a story? One late arrival means nothing. A pattern means she treats other people's time as optional, and you'll eventually be other people.

Her family. Meet them if you can, and watch how she is around them. You don't need a perfect family, because almost nobody has one. You want to see whether she's loyal, respectful and honest with the people she can't escape. How she carries herself with her mother is a decent preview of how she'll carry herself with you in year twelve.

Her work. Does she do the job properly when nobody's checking? Does she talk about her employer with some fairness, or does everyone who ever managed her turn out to be an idiot? Complaining is normal. A person who's never once the problem is a person who hasn't looked.

Her money. You don't need her tax returns on date three. You do want to know whether she lives within her means, whether she gives anything away, and what she thinks debt is. Someone who treats a credit card like free money will treat a joint account the same way.

A disagreement. This one you can't fake and shouldn't manufacture. When you do disagree, even about restaurants, does she say so plainly, go quiet and punish you, or tell you later to a third party? A woman who can say "I see it differently" and stay warm is worth a great deal.

Ask questions that make her choose

Most dating questions are softballs. "What do you like to do for fun?" gets you a brochure.

Better questions describe a trade-off, because values only show when two good things collide:

• "If you got a job offer that doubled your pay but meant moving away from your family, how would you think about it?"
• "When you picture the first few years of kids, who's home, and how do you feel about that?"
• "What's something you've given up because it was the right thing, even though you wanted it?"
• "When was the last time you apologized first?"

Don't fire these like an interview panel. Ask one over dinner and then shut up. Listen for the speed of the answer as much as the content. Somebody who's thought about it says something specific and slightly uncomfortable. Somebody who hasn't says "oh, I'd just see how it goes."

Listen also for what she does with a question about you. Tell her honestly what you'd choose, even if it's not the answer she's hoping for. Her reaction is data. You aren't looking for agreement on every point. You're looking for whether she can hear a conviction different from hers without turning cold or turning it into a debate to win.

Do your own list first

You can't spot a mismatch if you don't know what you're matching against.

Before the next date, write down five things you won't bend on in a marriage. Not preferences. Convictions. Whether you want children and how you'd raise them. What faithfulness means to you in practice. How you handle money. What role extended family plays. How you each treat a commitment when it stops being fun.

If you struggle to write it, that's useful information about where you stand. A man who hasn't decided what he's for will be easily moved by whoever's most charming in the room. It's the same idea behind being someone worth choosing: the work on yourself comes first, and it makes every judgment afterward sharper.

Then be honest about which of the five are true dealbreakers and which are strong preferences. Mixing them up is how good men walk away from good women over nothing, and how others talk themselves into the wrong one.

Give it time, then say it out loud

Values take a while to show, which is one reason to treat the early months as a period of watching. What the first three months are actually for lays that out. Don't announce a verdict at week three, and don't ignore what you've seen at month five just because you've gotten attached.

When something bothers you, say it while it's still small. Have the hard conversations while they're still cheap covers how. A short, calm "I noticed this, and it matters to me" tells you more than six more months of hoping it'll sort itself out.

And when you find a real mismatch on a core conviction, don't gamble on changing her. People can grow, but you can't schedule it, and a marriage isn't a renovation project. Wanting different things about children, honesty or fidelity doesn't make either of you a villain. It means you aren't each other's person. Tell her kindly and plainly, and let her go find the man who is. Dragging it out is the unkind choice, however gentle it feels.

When the evidence points the other way, and she's honest, steady, kind to people who can't repay her, and says what she means, stop auditing. At some point you stop dating and choose.

Hobbies get you to the first dinner. Character gets you to the thirtieth anniversary. Date for the second one.