Мне нравится честность тех людей, которые говорят прямо.

Because нравиться works differently from English to like.

In Russian, the pattern is closer to:

• Мне нравится X = X is pleasing to me
• literally: To me, X pleases

So:

• мне = to me (dative case)
• нравится = is pleasing / pleases
• честность... = the thing that is pleasing

That is why Я нравится is wrong. Я means I, but Russian does not use I like X with нравиться the way English does.

Because with нравиться, the person who experiences the liking goes in the dative.

Compare:

• Мне нравится эта книга. = I like this book.
• Ему нравится музыка. = He likes music.
• Нам нравятся эти люди. = We like these people.

So in your sentence:

• мне = to me

This is one of the most important patterns to learn with нравиться.

Because the grammatical subject here is честность, and честность is singular.

Russian makes нравиться agree with the thing being liked, not with the person who likes it.

So:

• Мне нравится честность.
  Honesty is singular, so нравится is singular.

But:

• Мне нравятся эти люди.
  These people is plural, so нравятся is plural.

In your sentence, even though людей is plural, the main thing being liked is честность.

It is in the nominative case.

That is because честность is the grammatical subject of нравится:

• Мне нравится честность...
• literally: Honesty ... is pleasing to me

So even though English might make you think of honesty as the object of like, in Russian with нравиться it behaves like the subject.

Because this part means of those people, and Russian uses the genitive case for that relationship.

So:

• те = those
• тех = genitive plural of те
• люди = people
• людей = genitive plural of люди

Together:

• честность тех людей = the honesty of those people

This is a very common Russian structure:

• характер этого человека = the character of this person
• мнение моих друзей = the opinion of my friends
• честность тех людей = the honesty of those people

Because the case of которые depends on its role inside the relative clause, not on the case of людей.

Let’s break it down:

• тех людей = of those people
• которые говорят прямо = who speak frankly/directly

Inside the clause которые говорят прямо, the word которые is the subject of говорят. Since it is the subject, it must be in the nominative plural.

So:

• людей is genitive because of честность тех людей
• которые is nominative because who is doing the speaking

This is very normal in Russian.

It means who or that in the sense of a relative pronoun.

So:

• те люди, которые говорят прямо = those people who speak frankly
• люди, которые... = people who...

Russian uses который to connect a noun to more information about it, just like English who/which/that.

In your sentence, которые refers back to людей.

Because Russian normally puts a comma before a relative clause introduced by который.

So:

• люди, которые говорят прямо
• книга, которую я читаю
• дом, в котором он живёт

This comma is standard in Russian punctuation.

Even when English might sometimes avoid or reduce punctuation, Russian keeps the comma in this kind of structure.

Here прямо means something like:

• frankly
• directly
• plainly
• straightforwardly

So говорят прямо means speak openly and directly, without hiding what they mean.

It does not mean physical straightness here. It is an adverb describing the manner of speaking.

A close English sense would be:

• people who speak frankly
• people who say things directly

Because Russian often uses the present tense to talk about a general characteristic or habitual behavior.

So:

• люди, которые говорят прямо = people who speak frankly

This does not mean they are speaking right now at this exact moment. It means this is the kind of people they are, or what they generally do.

English does the same thing:

• I like people who tell the truth
• She respects people who work hard

Because the sentence describes a general, repeated, or characteristic action, not one completed act.

• говорить (imperfective) = to speak, to say, in a general or ongoing sense
• сказать (perfective) = to say, to state once, to complete the act of saying

Here the meaning is:

• people who tend to speak directly
• people who are straightforward when they speak

So the imperfective говорят is the natural choice.

Yes, sometimes it could be, but the nuance changes a little.

• Мне нравится честность тех людей, которые говорят прямо.
  = I like the honesty of those people who speak frankly.

• Мне нравится честность людей, которые говорят прямо.
  = I like the honesty of people who speak frankly.

With тех, the sentence feels a bit more specific or contrastive, as if you are pointing to a particular group: those people.

Without тех, it sounds more general.

Yes, Russian word order is flexible, but the neutral version is the one you have.

Your sentence:

• Мне нравится честность тех людей, которые говорят прямо.

This is natural and clear.

You might also hear variations for emphasis, such as:

• Честность тех людей, которые говорят прямо, мне нравится.

This puts more focus on честность.

But for a learner, the original order is the safest and most natural to use.

Yes, you could, but it sounds different.

• Мне нравится... = I like...
• Я люблю... = I love...

Любить is stronger and often more emotional. In many contexts, нравиться sounds more natural for preferences and approval.

So:

• Мне нравится честность тех людей... = I like / appreciate the honesty of those people...
• Я люблю честность тех людей... = I love the honesty of those people...

The second one is possible, but stronger.

Yes, честность is a very natural word for honesty.

It refers to being honest, truthful, morally straightforward.

In this sentence, it fits well because the second part describes people who говорят прямо—people who speak openly and directly. That matches the idea of честность.

A nearby word is искренность:

• честность = honesty
• искренность = sincerity

They overlap, but they are not exactly the same.
Your sentence with честность emphasizes honest straightforwardness.

Because the structure is:

• Мне нравится [честность тех людей]
• and then которые говорят прямо describes людей

So the main skeleton is:

• Мне нравится честность. = I like honesty.

Then Russian adds:

• честность тех людей = the honesty of those people
• которые говорят прямо = who speak frankly

So the whole noun phrase is:

• честность тех людей, которые говорят прямо

That entire phrase is the thing that нравится.

This kind of long noun phrase is very common in Russian.