It is read:
しんらい は だいじ です。
A more natural way to write it, without learner spaces, is:
信頼は大事です。
Romanization:
Two useful pronunciation notes:
Because は is acting as the topic particle, and when it is used as a particle, its pronunciation is wa, not ha.
This is one of the first unusual spelling/pronunciation points learners meet in Japanese.
So:
In this sentence, 信頼は means as for trust or regarding trust.
This is a very common question.
In a basic explanation:
So:
The version with は sounds more like a general statement about trust. The version with が can sound more contrastive or more focused, depending on context.
For a simple standalone statement, 信頼は大事です is very natural.
Yes, 大事（だいじ） means important, and it behaves like a na-adjective in Japanese.
Japanese learners often learn two broad adjective groups:
大事 is in the na-adjective group.
In this sentence, it is being used at the end as the predicate:
That is why there is no な here.
Because な is only used when a na-adjective comes directly before a noun.
Compare:
But when the adjective is at the end of the sentence, you do not use な:
So:
です makes the sentence polite.
It is often called the copula, but for beginners the most useful idea is:
So:
Both mean the same thing, but です is more appropriate in neutral polite speech, in class, with strangers, and in many everyday situations.
Yes. 大切（たいせつ） is another very common word meaning important, valuable, or precious.
So both are natural:
Very roughly:
But in many situations, they are very close in meaning.
Japanese does not have articles like English a, an, and the.
So 信頼 can simply mean trust in a general sense, depending on context.
That is why 信頼は大事です naturally means:
rather than needing something like:
Japanese lets context handle that kind of distinction.