Bana yalan söyleme; doğruyu duyunca daha rahat oluyorum.

Because bana means to me, and that is the role needed here.

The verb pattern is often:

• birine bir şey söylemek = to say/tell something to someone

So:

• bana = to me
• yalan söyleme = don’t lie / don’t tell lies

Using ben would mean I, which would not fit here.

Yes. Yalan söylemek is the normal everyday expression for to lie.

Literally:

• yalan = lie / falsehood
• söylemek = to say / tell

So literally it is something like to say a lie, but in natural English we translate it as to lie.

This is a fixed, very common Turkish expression.

Here söyleme is the negative informal singular imperative.

Formation:

• söyle- = verb stem from söylemek
• -me = negative imperative marker for you singular informal

So:

• Söyle! = Say it!
• Söyleme! = Don’t say it!

In this sentence, because the object is yalan, it means Don’t lie to me.

This -me is not the same thing as the noun-making suffix you may also see in Turkish. Here the command context makes it clear that it is an imperative.

Yes. Söyleme is for informal singular you.

Other forms:

• söylemeyin = don’t say / don’t lie
  used for plural you or formal/polite you
• söylemesin = let him/her not say
• söylemeyelim = let’s not say

So if you were speaking politely, you would say:

• Bana yalan söylemeyin.

The semicolon links two closely related ideas:

• Bana yalan söyleme = a request/command
• doğruyu duyunca daha rahat oluyorum = the reason for that request

So the second part explains the first part: Don’t lie to me; I feel better when I hear the truth.

In everyday writing, a comma or even a full stop could also appear, depending on style. You could also rewrite it with çünkü:

• Bana yalan söyleme, çünkü doğruyu duyunca daha rahat oluyorum.

The -yu is the accusative case ending, used here because doğruyu is the definite direct object.

Breakdown:

• doğru = right / correct / true
• doğruyu = the truth / the correct thing

The y is a buffer consonant. Turkish often inserts y when a vowel-final word takes a vowel-initial ending.

So:

• doğru + -(y)u → doğruyu

In this sentence, it means something like the truth as a specific thing being heard.

Yes, doğru often means right, correct, or true. But Turkish can also use it as a noun-like word meaning what is true / the truth / the right thing.

So here:

• doğruyu duymak = to hear the truth

A very similar alternative would be:

• gerçeği duymak = to hear the truth

Both are natural. Gerçek is more directly reality / truth, while doğru can carry the sense of what is true/correct.

Duyunca means when (someone) hears, upon hearing, or once (someone) hears.

It comes from:

• duymak = to hear
• verb stem: duy-
• -unca / -ince = a converb ending meaning when / once / upon

So:

• duyunca = when hearing / when one hears

This kind of form connects one action to another without making a full separate clause with tense/person marking.

Examples:

• Eve gelince beni ara. = Call me when you get home.
• Seni görünce sevindim. = I was happy when I saw you.

In this sentence, the understood subject is I, because the main verb oluyorum clearly means I become / I feel.

So the natural reading is:

• (Ben) doğruyu duyunca daha rahat oluyorum.
• When I hear the truth, I feel more at ease.

Turkish often leaves out subject pronouns when they are already clear from the verb ending or the context.

If needed for emphasis, Turkish could add ben:

• Ben doğruyu duyunca daha rahat oluyorum.

But normally it is omitted.

Because duymak and dinlemek are different:

• duymak = to hear
• dinlemek = to listen

Here the meaning is when I hear / learn the truth, not when I listen to the truth. So duymak is the correct choice.

Also, duymak can sometimes mean not just physical hearing, but also to hear about / find out / learn something, which fits this sentence very well.

Daha means more, so:

• rahat = comfortable / at ease / relieved
• daha rahat = more at ease / more comfortable / more relieved

Even though English often wants an explicit comparison, Turkish does not always state it. The comparison is understood from context:

• hearing the truth makes the speaker feel more at ease than being lied to or left uncertain

So daha rahat sounds very natural here.

Because rahat oluyorum emphasizes becoming or ending up in that state.

Compare:

• rahatım = I am comfortable / I’m at ease
• rahat oluyorum = I become comfortable / I start to feel at ease

In this sentence, the idea is not just a static state. It is a reaction:

• When I hear the truth, I feel more at ease.

So oluyorum works well because it shows that hearing the truth leads to that feeling.

Oluyorum is the present continuous form of olmak.

Breakdown:

• ol- = stem
• -uyor = present continuous marker
• -um = I

So literally it is I am becoming / I become.

In Turkish, the present continuous is often used not only for something happening right now, but also for:

• repeated behavior
• personal habits
• typical reactions
• generally valid present situations

So here it means something like:

• I tend to feel more at ease when I hear the truth.

That is why oluyorum sounds natural.

Yes, Turkish word order is flexible, but the version in the sentence is very natural.

Current order:

• Bana yalan söyleme; doğruyu duyunca daha rahat oluyorum.

This keeps the important information in a natural flow:

1. request
2. explanation

Turkish often puts the verb near the end, and elements can move for emphasis. For example:

• Doğruyu duyunca ben daha rahat oluyorum.
• Ben doğruyu duyunca daha rahat oluyorum.

These are possible, but they add different emphasis. The original version is neutral and natural.

Yes. A few natural alternatives are:

• Bana yalan söyleme; gerçeği duyunca daha rahat oluyorum.
• Bana yalan söyleme; doğruyu duyunca rahatlıyorum.
• Bana yalan söyleme, çünkü doğruyu duyunca daha rahat oluyorum.

These are all close in meaning, but the original sentence is already perfectly natural.