Not certainty. Certainty is not available, and waiting for it is how people spend three years engaged to the idea of being engaged.
What you should have is a specific set of things seen, discussed, and sayable out loud.
Things you should have seen
Them under stress. Tired, disappointed, late, unwell, under pressure at work. Character under load is different from character at dinner, and a marriage is mostly conducted under load.
Them with their family. Not a single polite lunch. Enough to know what the dynamics are and how they behave inside them.
A real disagreement, and what happened afterwards. If you have never had one, you do not yet know the most important thing about this relationship. Couples who have never argued have usually not been tested, not achieved harmony.
How they handle money. Not the conversation — the behaviour.
One genuinely hard thing, together. An illness, a loss, a job ending. If it has not happened, that is nobody’s fault, but it is missing information and worth acknowledging as such.
Things you should have discussed
Money with actual numbers. Children, specifically. The Jewish home, concretely. Where you will live and how close to whose family. What happens when your families and your marriage want different things.
The full list is in the article on pre-engagement questions, and the tool builds the version that fits your situation.
Things you should be able to say out loud
Why this person. To someone who will push back, with specifics rather than adjectives. “Because she tells me the truth even when it costs her” is a reason. “Because she is amazing” is not.
What you are worried about. Everyone has something. People who can name theirs are in better shape than people who insist they have none, because the unnamed ones do not go away — they just arrive later.
What you would find hard about being married to them. If you cannot answer, you are probably still in the phase where they have no flaws, and that phase is not a good moment to make a permanent decision.
The practical things people forget
Anything that needs sorting first. A get, if either of you was married Jewishly before. Any open question about Jewish status in either family. Immigration, if relevant. These are much easier to address before an engagement than during wedding planning, and people discover them at the worst moment with dismal regularity.
Genetic carrier screening. Medically recommended before conception and widely available through Jewish community programmes. Better done now than in a pregnancy.
What the wedding actually needs to be. If either family cares which authority recognises it, find out what that requires before you book anything.
What is not a good reason
Being the right age. A sibling getting married. Family pressure. Having been together a long time. Fear of starting again. Fear that this is the best available.
None of these are unusual and all of them are bad foundations, mostly because they are reasons to be married rather than reasons to marry this person.
Doubt
Nearly everyone has some. What matters is which kind.
Doubt about something specific — a timeline, a behaviour, a difference you have not resolved — is information. It names itself, it stays the same over months, and it should be addressed before you proceed.
Free-floating doubt — a sense that something is missing, that there might be someone better — moves around, attaches to different things, and is usually more about you than about them.
If you cannot tell which you have, that is a good moment to talk to someone outside it. Pre-Marriage Alignment coaching exists largely for this question.