Tro is the verb you use to express belief, guesses, and predictions — anything you hold to be probably true but cannot vouch for as fact. It is the "uncertain" member of the famous Norwegian trio tro / synes / mene, all three of which English flattens into "think." Getting tro right is half the battle of sounding natural when you give an opinion in Norwegian. It is also a weak Class 4 verb, the small but high-frequency class of verbs whose stems end in a stressed vowel.
Conjugation
Tro belongs to weak Class 4: the stem ends in a long, stressed vowel (tro-), and the past tense doubles the following consonant and adds -dde. The supine adds -dd. This -dde / -dd pattern is the signature of Class 4.
| Form | Norwegian | English |
|---|---|---|
| Infinitive | å tro | to believe / think |
| Present | tror | believe(s) / think(s) |
| Preterite (past) | trodde | believed / thought |
| Supine (perfect) | har trodd | have believed / thought |
| Imperative | tro! | believe! |
| Present participle | troende | believing |
The spelling is the trap. The preterite is trodde with a double d (and double, not single, because the vowel before it is short here even though the infinitive vowel is long). The supine is trodd. English speakers very often write trode with one d — that is simply wrong.
Sense 1: tro = believe / think (something is probably true)
The core meaning is to hold something as probably true — a belief, a guess, an estimate. It is followed by at + a clause (often droppable in speech), or by a direct object. This is the "I reckon / I guess / I believe" sense.
Jeg tror det regner ute — ta med paraply.
I think it's raining outside — take an umbrella.
Jeg tror (at) toget går klokka sju.
I think the train leaves at seven.
Hun trodde at vi hadde glemt bursdagen hennes.
She thought (believed) we had forgotten her birthday.
Notice the logic: in every case the speaker is making a claim about what is the case in the world that they cannot confirm. "I think it's raining" is a guess about a fact. That is tro territory. If you can replace English "think" with "believe" or "guess" without changing the meaning, tro is correct.
Sense 2: tro + a person = believe (someone)
Tro can take a person as its object, meaning to believe what that person says — to trust their word on a particular point.
Du må tro meg — jeg så det med egne øyne.
You have to believe me — I saw it with my own eyes.
Hun trodde ham ikke da han sa han var lege.
She didn't believe him when he said he was a doctor.
Ingen trodde på det han fortalte.
Nobody believed what he was saying.
Sense 3: tro på (believe in)
With the preposition på, tro på means to believe in — in a person's existence or reliability, in God, in a cause, in someone's abilities. This is a fixed verb + preposition pair.
Tror du på Gud?
Do you believe in God?
Jeg tror på deg — du klarer eksamen.
I believe in you — you'll pass the exam.
Har du virkelig trodd på julenissen helt til nå?
Have you really believed in Santa Claus right up until now?
The distinction mirrors English neatly: tro noe = believe something (is true); tro på noe/noen = believe in it/them. Keep the på and you keep the "in."
The big one: tro vs synes vs mene
All three become "think" in English, which is exactly why English speakers misuse them. The rule is about what kind of mental act you are performing.
| Verb | Means | Use it for |
|---|---|---|
| tro | believe / guess (uncertain fact) | predictions, estimates, things you can't verify |
| synes | find / feel (subjective impression) | personal taste, how something strikes you |
| mene | hold the opinion / mean (considered view) | reasoned positions, what you intend to say |
Jeg tror det blir regn i morgen.
I think (predict) it'll rain tomorrow.
Jeg synes filmen var kjedelig.
I think (find) the film was boring.
Jeg mener at staten bør betale.
I think (am of the opinion) that the state should pay.
Here is the test. Tro = you are guessing at a fact in the world (could turn out right or wrong). Synes = you are reporting your subjective reaction (no right or wrong — it is your taste). Mene = you are stating a reasoned opinion you could defend. "I think it'll rain" is a prediction → tror. "I think the soup is too salty" is a personal impression → synes. "I think the law is unjust" is a considered position → mener. This three-way split is the single most useful distinction in this part of the grammar, and it is treated in full on the synes/tror/mener page.
Common Mistakes
❌ Jeg trode at hun kom.
Incorrect — Class 4 preterite needs double d.
✅ Jeg trodde at hun kom.
I thought she was coming.
❌ Jeg tror filmen var god.
Wrong verb — a personal impression, not a guess at fact.
✅ Jeg synes filmen var god.
I think (find) the film was good.
❌ Tror du Gud?
Incorrect — 'believe in' needs på.
✅ Tror du på Gud?
Do you believe in God?
❌ Jeg tror at vi bør stenge skolene.
Sounds like a guess; a reasoned stance wants mene.
✅ Jeg mener at vi bør stenge skolene.
I think (am of the opinion) that we should close the schools.
❌ Har du trodt på det?
Incorrect supine — it's trodd, not trodt.
✅ Har du trodd på det?
Have you believed in it?
Key Takeaways
- tro / tror / trodde / trodd — weak Class 4, double-d in the past (trodde) and supine (trodd).
- tro noe = believe/guess something is true; tro noen = believe a person's word.
- tro på = believe in (God, a person, a cause).
- In the tro / synes / mene trio, tro is the uncertain-fact member — predictions and guesses, never subjective taste or reasoned opinion.
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- synes vs tror vs mener: Three Ways to 'Think'B1 — synes is your subjective verdict on something you've experienced, tror is your belief or guess about an uncertain fact, and mener is your reasoned, considered opinion — English 'think' splits three ways.
- Weak Class 4: -dde / -dd (bo, tro)A2 — The small but high-frequency class for vowel-final verbs — they double the d (bo → bodde → har bodd, tro → trodde → har trodd) — plus the related irregular ha → hadde → hatt.
- synes (to think / find / seem)B1 — Conjugation and usage of the deponent -s verb synes (synes / synes / syntes / har syntes): expressing subjective opinion ('I find / I feel'), the 'be visible / seem' sense, and the contrast with tro and mene.
- mene (to mean / opine)B1 — Conjugation and usage of the weak Class 2 verb mene (mene / mener / mente / har ment): holding a considered opinion, the meaning 'to mean / intend', mene at and mene det (be serious), and the contrast with synes and tro.