Si te viene bien, el jueves por la tarde me encaja mejor.

It means something like if it suits you, if it works for you, or if it’s convenient for you.

Literally, venir bien is to come well, but in Spanish it is a very common idiomatic expression meaning that something is convenient or suitable for someone.

So:

• Te viene bien = It works for you / It suits you
• No me viene bien = It doesn’t work for me

In this sentence, Si te viene bien... is a polite way to say If that works for you...

The te means to you.

Spanish often uses indirect object pronouns with expressions like this:

• Me viene bien = It suits me
• Te viene bien = It suits you
• Le viene bien = It suits him/her/you (formal)

So te viene bien literally works like it comes in a good way to you, but in natural English we say it works for you.

Because venir bien is just the standard expression in Spanish for saying that something is convenient or suitable.

Some common examples:

• ¿Te viene bien mañana? = Would tomorrow work for you?
• No me viene bien ahora. = Now isn’t a good time for me.
• Nos viene bien quedar a las seis. = Meeting at six works for us.

It is not something you translate word for word. It is simply a fixed expression you learn as a chunk.

Here, el jueves means Thursday, usually understood as this Thursday or next Thursday, depending on context.

Spanish often uses the definite article with days of the week:

• el lunes
• el jueves
• el sábado

In context, el jueves por la tarde means Thursday afternoon.

Be careful: depending on context, los jueves means on Thursdays / every Thursday.

So:

• el jueves = Thursday / this coming Thursday
• los jueves = Thursdays in general

In Spain, the usual expression is:

• por la mañana = in the morning
• por la tarde = in the afternoon
• por la noche = at night / in the evening

So el jueves por la tarde is the normal Spanish way to say Thursday afternoon.

In some parts of Latin America, en la tarde can also be heard, but for Spanish from Spain, por la tarde is the most natural choice.

Me encaja mejor means it fits me better, it suits me better, or more naturally here, that works better for me.

The verb encajar literally means to fit or to slot into place, but it is also used for schedules, plans, and arrangements.

So in this sentence:

• me = for me / to me
• encaja = fits, works
• mejor = better

Together: it works better for me

They are similar, but not identical.

• te viene bien asks whether something is convenient for the other person.
• me encaja mejor says that something fits your own schedule better.

So the sentence is doing two things:

1. Si te viene bien = If it works for you
2. el jueves por la tarde me encaja mejor = Thursday afternoon works better for me

This makes the sentence polite and balanced: you mention your preference, but only if it is also convenient for the other person.

Yes, absolutely.

El jueves por la tarde me viene mejor is very natural and probably even more common in everyday conversation.

The difference is small:

• me viene mejor = works better for me
• me encaja mejor = fits better into my schedule / suits me better

Encajar can feel slightly more like fitting into your timetable, but both are correct and natural here.

Because the me shows who it works better for.

Compare:

• Me encaja mejor = It works better for me
• Te encaja mejor = It works better for you
• Nos encaja mejor = It works better for us

Spanish often includes these object pronouns where English would use for me, for you, etc.

Because this is a normal, real possibility, not a hypothetical or unlikely situation.

In Spanish, with si meaning if, the present indicative is used for real/open conditions:

• Si te viene bien, quedamos el jueves.
• Si tienes tiempo, llámame.

You would not say si te venga bien here.

A past subjunctive form like si te viniera bien would make it more hypothetical or tentative:

• Si te viniera bien, podríamos quedar el jueves. = If Thursday afternoon suited you, we could meet.

So in your sentence, the indicative is correct because the speaker is making a straightforward suggestion.

It is informal because it uses te, which is the informal you singular.

For a formal version, you could say:

• Si le viene bien, el jueves por la tarde me encaja mejor.

For plural:

• Si os viene bien... = informal plural in Spain
• Si les viene bien... = formal plural, or common plural form in many varieties outside Spain

Here it means one specific Thursday afternoon, not Thursdays in general.

That is because:

• el jueves in this context refers to a particular Thursday
• los jueves would mean on Thursdays / every Thursday

So:

• El jueves por la tarde me encaja mejor. = Thursday afternoon works better for me.
• Los jueves por la tarde me encajan mejor. = Thursday afternoons work better for me.

The order is very natural in Spanish:

• Si te viene bien, ... = first the condition
• el jueves por la tarde = then the proposed time
• me encaja mejor = then the speaker’s preference

This is similar to English: If that works for you, Thursday afternoon works better for me.

You could change the order a little and still be understood, but this version sounds smooth and natural.

Yes. It sounds polite, cooperative, and natural.

It is polite because the speaker:

• first checks whether the time is convenient for the other person: Si te viene bien
• then states a preference, not a demand: me encaja mejor

So it feels softer than something like:

• Quedamos el jueves por la tarde. = We’re meeting Thursday afternoon.

Your sentence sounds more like a suggestion than an imposition.