Мне трудно выразить свои чувства.

Because this sentence uses a very common Russian pattern:

• dative pronoun/noun + predicate word + infinitive

So:

• мне = to me / for me
• трудно = difficult
• выразить = to express

Literally, the structure is something like:

• To me, it is difficult to express my feelings.

Russian often uses the dative in sentences about someone’s experience or state:

• Мне холодно. = I am cold.
• Мне интересно. = I am interested / It’s interesting to me.
• Мне трудно говорить. = It’s hard for me to speak.

So мне is exactly what Russian grammar requires here.

It is simply omitted.

In present-tense Russian, быть (to be) is usually not said in sentences like this. So where English says:

• It is hard

Russian just says:

• трудно

This is very normal. Russian does this constantly:

• Он врач. = He is a doctor.
• Мне грустно. = I am sad.
• Здесь тихо. = It is quiet here.

So Мне трудно выразить свои чувства is a complete sentence even without a word meaning is.

Here трудно is not really an adjective modifying a noun. It is a predicate word (often called a category of state word, or predicative adverb in learner materials).

It means:

• difficult
• hard

but in a sentence like this it functions as the main predicate:

• Мне трудно. = It is hard for me.
• Мне трудно понять это. = It is hard for me to understand this.

It does not change for gender, number, or case here. It stays трудно.

A learner often notices that it looks like the neuter short form of трудный, and historically that is related, but in this kind of sentence it is best to learn it as a fixed predicative word meaning it is difficult / hard.

This is about aspect.

• выразить = perfective
• выражать = imperfective

With трудно + infinitive, both aspects are possible, but they give slightly different shades of meaning.

выразить

This often suggests:

• expressing them successfully
• putting them into words
• getting the act done

So:

• Мне трудно выразить свои чувства.

sounds very natural for It’s hard for me to express my feelings.

выражать

This would focus more on:

• the process
• a general habit
• expressing feelings in general/regularly

So:

• Мне трудно выражать свои чувства.

is also possible and natural, but feels a bit more like:

• I have difficulty expressing my feelings
• It’s hard for me to be expressive about my feelings

In many contexts, both work. The perfective version is especially common when the speaker means I can’t quite put my feelings into words.

Because Russian usually prefers the reflexive possessive свой when the possessor is the same person as the subject or the understood experiencer.

Here the person experiencing the difficulty is мне (I / me), and the feelings belong to that same person. So Russian naturally says:

• свои чувства = one’s own feelings / my own feelings in this context

This is more idiomatic than мои чувства.

Compare:

• Я люблю свою семью. = I love my family.
• Он нашёл свои ключи. = He found his keys.

Using мои is not impossible, but it often sounds more emphatic, contrastive, or less natural in ordinary speech:

• Мне трудно выразить мои чувства may sound like you are contrasting my feelings with someone else’s.

So for a neutral sentence, свои is the best choice.

Yes, you can, but the meaning becomes less explicit.

• Мне трудно выразить свои чувства = It’s hard for me to express my feelings.
• Мне трудно выразить чувства = It’s hard for me to express feelings.

Without свои, the sentence sounds more general or less anchored. It might still be understood as my feelings from context, but Russian often prefers свои here to make the relationship clear and natural.

So if you specifically mean my own feelings, keeping свои is the safest and most idiomatic choice.

Because Russian, like English, often talks about a person’s emotional inner life in the plural:

• чувства = feelings

This is very natural when you mean emotions in general.

If you used the singular:

• чувство

that would usually mean:

• one feeling
• a single emotion
• sometimes even a sense or a faculty depending on context

So:

• Мне трудно выразить свои чувства. = It’s hard for me to express my feelings.

is the normal version for this meaning.

It is in the accusative plural.

The verb выразить takes a direct object, so чувства is the thing being expressed.

For this noun, the accusative plural looks the same as the nominative plural:

• nominative plural: чувства
• accusative plural: чувства

That is why the form does not visibly change.

Also, свои matches it:

• свои чувства = accusative plural

No, Russian word order is flexible.

The neutral, standard order is:

• Мне трудно выразить свои чувства.

This presents the idea smoothly and naturally.

But you can move parts around for emphasis:

• Свои чувства мне трудно выразить.
  Emphasis on my feelings
• Выразить свои чувства мне трудно.
  Emphasis on the action to express
• Трудно мне выразить свои чувства.
  More emotional or marked

For most learners, the original order is the best one to use unless you have a specific reason to emphasize something.

Yes. That is very common and natural.

Comparison

• трудно = hard, difficult
• сложно = difficult, complicated
• тяжело = hard, emotionally or physically heavy

So these are all possible:

• Мне трудно выразить свои чувства.
• Мне сложно выразить свои чувства.
• Мне тяжело выразить свои чувства.

Nuance

• трудно is very standard and neutral
• сложно is also common, often sounding a bit more conversational in modern speech
• тяжело adds more emotional weight, like it’s painful / emotionally hard

The stress is:

• Мне́ тру́дно вы́разить свои́ чу́вства.

Word by word:

• мне — one syllable
• тру́дно — stress on the first syllable
• вы́разить — stress on вы́
• свои́ — stress on the last syllable
• чу́вства — stress on the first syllable

A rough pronunciation guide:

• mnye TROOD-na vya-ra-zit' sva-EE CHOOV-stva

A couple of notes:

• мне begins with a consonant cluster that may feel tricky at first.
• In natural speech, unstressed vowels are reduced, so some vowels sound less clear than they look in spelling.

It is neutral and works in both spoken and written Russian.

It does not sound especially formal, and it does not sound slangy either. You could use it:

• in conversation
• in writing
• in therapy or emotional discussion
• in a book or dialogue

If you want something even more conversational, сложно is a common alternative:

• Мне сложно выразить свои чувства.

But the original sentence is completely normal and natural.

Sometimes yes, depending on context, but feelings is usually the most direct translation.

чувства

can mean:

• feelings
• emotions
• sentiments

эмоции

more specifically means:

• emotions

So:

• выразить свои чувства = express one’s feelings
• выразить свои эмоции = express one’s emotions

Both are possible in Russian, but чувства often sounds a bit broader and more personal. For the sentence you gave, feelings is usually the best match.