Learn Hardcore Spanish (Spain): Ahora sigo siendo un poco tímida, pero intento ser sincera cuando doy mi opinión. - Now I am still a bit shy, but I try to be honest when I give my opinion.

soy un poco tímida = I’m a bit shy (a present fact, no extra idea of “still”).
todavía soy un poco tímida = I’m still a bit shy (you expected change, but it hasn’t happened).
sigo siendo un poco tímida = I keep on being / I remain a bit shy (clearly links your current shyness to how you were before; there has been no change).

So sigo siendo stresses that the situation hasn’t changed over time, more than simple soy does.

Grammatically, what is the structure of sigo siendo? Is siendo a kind of infinitive?

No. siendo is the gerund (gerundio) of ser.

The structure is:

seguir (conjugated) + gerund

So:

sigo = 1st person singular, present of seguir.
siendo = gerund of ser.

This seguir + gerundio construction means “to continue doing something”:

Sigo estudiando español. = I keep studying Spanish / I’m still studying Spanish.
Sigue lloviendo. = It’s still raining.

In your sentence, sigo siendo = “I continue to be / I remain”.

Why are tímida and sincera feminine? Does that mean the speaker is female?

Yes. In Spanish, adjectives must agree in gender and number with the noun (or pronoun) they describe.

tímido (m.), tímida (f.)
sincero (m.), sincera (f.)

Because the implied subject is yo, and the speaker is presenting themselves as feminine, the adjectives are:

un poco tímida
ser sincera

If the speaker were male, they would say:

Ahora sigo siendo un poco tímido, pero intento ser sincero cuando doy mi opinión.

For a mixed or plural group:

Somos un poco tímidos, pero intentamos ser sinceros…

In pero intento ser sincera, why is it intento ser and not intento de ser? And how is this different from trato de ser?

Here intento is the verb intentar, conjugated in the first person singular: (yo) intento = “I try”.

As a verb, it goes directly with an infinitive:
- Intento ser sincera. = I try to be honest.
- Intento mejorar. = I try to improve.

You do not add de after the verb intentar.

de appears with the noun intento:

Hago un intento de ser sincera. = I make an attempt to be honest.

So:

intento ser (verb) ✅
intento de ser (treating intento as a noun) ❌ in this sentence.

tratar de + infinitive is very similar to intentar:

Trato de ser sincera. = I try to be honest.

In everyday European Spanish, intentar and tratar de are almost interchangeable, with only a slight nuance: tratar de can sometimes feel a bit more like “make an effort to”, but in many contexts there’s no real difference.

Why is it ser sincera and not estar sincera?

Because sincera here refers to a general, characteristic way of being, not just a temporary state.

Very broadly:

ser + adjective → inherent or usual characteristic:
- ser sincera, ser tímida, ser amable
  (to be an honest/shy/kind person in general)
estar + adjective → temporary state or condition:
- estar nerviosa, estar cansado
  (to be nervous/tired at the moment)

So intento ser sincera = “I try to be an honest person / I try to speak honestly (as a general rule)”.

estar sincera is possible but much rarer; it sounds like “to be in a frank mood right now”:

Hoy estoy muy sincera. = Today I’m being very frank (more than usual).

In your sentence the idea is a general attitude, so ser is the natural choice.

Why do we say doy mi opinión instead of digo mi opinión?

In Spanish, the common collocation is:

dar una opinión / dar mi opinión / dar tu opinión
= to give an opinion.

The verb dar is used with many abstract nouns:

dar consejos (to give advice)
dar una respuesta (to give an answer)
dar explicaciones (to give explanations)
dar las gracias (to give thanks)

So doy mi opinión is the standard way to say “I give my opinion”.

decir is “to say / to tell” specific words or information:

decir la verdad
decir algo
decir que…

decir mi opinión isn’t strictly ungrammatical, but it sounds unusual and less idiomatic than dar mi opinión. Native speakers normally say:

dar mi opinión
or simply opinar: Intento ser sincera cuando opino.

Is mi in mi opinión really necessary? Could you say la opinión or just opinión?

You need some kind of determiner; you can’t leave opinión bare in the singular.

Cuando doy opinión ❌ (ungrammatical)
Cuando doy mi opinión ✅
Cuando doy una opinión ✅ (when I give an opinion, in general)

Here, mi opinión is natural because you are talking about your own personal opinion.

If you say doy la opinión, it sounds like there is one specific, known “the opinion” that everyone is aware of. That is odd in this context. More natural options are:

cuando doy mi opinión (when I give my opinion)
cuando doy una opinión (when I give an opinion)
cuando opino (when I express an opinion)

Why is there no yo in the sentence? Would Ahora yo sigo siendo un poco tímida also be correct?

Spanish is a “pro‑drop” language: the subject pronoun is often omitted because the verb endings already show the subject.

sigo already tells us it is yo (1st person singular).
intento also clearly indicates yo.

So (Yo) sigo, (yo) intento: the yo is understood and normally left out unless you need emphasis or contrast.

Ahora yo sigo siendo un poco tímida… is grammatically correct, but it sounds like you are stressing I, e.g.:

Ahora yo sigo siendo un poco tímida, pero tú ya no.
(I’m still a bit shy, but you aren’t anymore.)

Without that contrast, the simple version without yo is the natural one.

Why is pero used here and not sino: … tímida, pero intento ser sincera …?

pero and sino both translate roughly as “but”, but they are used differently.

pero introduces a contrast or additional idea:
- Soy tímida, pero intento ser sincera.
  I’m shy, but I try to be honest.
sino is used only after a negation (no, nunca, nadie, etc.) and corrects what comes before:
- No soy tímida, sino reservada.
  I’m not shy, but rather reserved.
- No quiero té, sino café.

In your sentence there is no negation in the first part (no is not present), so you must use pero, not sino.

Could you say Ahora estoy siendo un poco tímida instead of Ahora sigo siendo un poco tímida?

You could say Ahora estoy siendo un poco tímida, but the meaning changes.

estoy siendo un poco tímida = I’m being a bit shy right now, in this situation (a temporary behaviour).
sigo siendo un poco tímida = I remain a bit shy as a general characteristic over time.

Spanish estar + gerundio describes an action or behaviour in progress at the moment:

Estoy hablando. = I’m speaking.
Estás siendo muy pesado. = You are being very annoying (right now).

Using it with tímida would focus on the current situation, e.g. apologising for your behaviour in this conversation:

Perdona, estoy siendo un poco tímida.

Your original sentence talks about your lasting personality, so sigo siendo (or simply soy) is the appropriate form.

Why is it un poco tímida and not un poco de tímida?

Because un poco is used differently with adjectives and nouns:

un poco + adjective/adverb:
- un poco tímida (a bit shy)
- un poco cansado
- un poco despacio
un poco de + noun:
- un poco de agua
- un poco de paciencia
- un poco de tiempo

In your sentence, tímida is an adjective, so the correct pattern is un poco tímida, without de.

Why is it cuando doy mi opinión with the indicative, and not cuando dé mi opinión with the subjunctive?

With cuando, Spanish uses either indicative or subjunctive depending on the meaning:

Indicative (as in cuando doy mi opinión) is used for:
- habitual or repeated actions
- present or past facts
Examples:
- Cuando tengo tiempo, leo. = When I have time, I read.
- Cuando era niña, jugaba en el parque. = When I was a child, I played in the park.
In your sentence, cuando doy mi opinión refers to something that typically happens whenever you give your opinion. It’s a general, habitual situation, so doy (indicative) is correct.
Subjunctive (cuando dé) is used when the action is:
- in the future
- uncertain / not yet realised
Example:
- Intentaré ser sincera cuando dé mi opinión en la reunión de mañana.
  I’ll try to be honest when I give my opinion in tomorrow’s meeting.

So:

Intento ser sincera cuando doy mi opinión. ✅
(habit, in general)
Intentaré ser sincera cuando dé mi opinión. ✅
(a specific future moment)