Questions & Answers about Chcę być sobą.
Because sobą is the instrumental form of the reflexive pronoun siebie.
In Polish, the expression być sobą is a fixed and very common phrase meaning to be oneself or to be true to oneself. After być, Polish often uses the instrumental case for what someone is, especially in expressions of identity, role, or state.
So:
- siebie = genitive/accusative form
- sobie = dative/locative form
- sobą = instrumental form
Here, only sobą is correct.
Because it follows chcę, which means I want.
In Polish, after verbs like chcieć (to want), you usually use another verb in the infinitive:
- Chcę spać. = I want to sleep.
- Chcę iść. = I want to go.
- Chcę być sobą. = I want to be myself.
So być is in the infinitive because it works just like to be in English after want.