"Kompreneble la patro ŝlosos la ĉambron."

Translation: Of course the father will lock the room.

[KingPlutoIX]

D-dad? Why are you locking that room?

[MauriceReeves]

La patro ŝlosas la ĉambron, ĉar li ne volas la knaboj vidi lian belegan filinon. Ĉiom la knaboj volas kisi la belegan knabinon. Ŝi estas tre belega kaj tre afablega, kaj ĉiom la knaboj pensas ke ili ŝin ami.

[MrMorley3]

Prenu malvarman duŝon, sinjoro! ;)

The sentence you wrote is 100% understandable, but here's a version with a few small corrections:
La patro ŝlosas la ĉambron, ĉar li ne volas, ke la knaboj vidu sian belegan filinon. Ĉiuj knaboj volas kisi la belegan knabinon. Ŝi estas tre belega kaj tre afablega, kaj la knaboj ĉiuj pensas, ke ili ŝin amas.

[traevoli]

Actually, you wouldn't use "sia" here because it's a subclause. "la knaboj vidu sian belegan filinon" means "the boys say their own beautiful daughter."

[MauriceReeves]

Dankon! I appreciate your help. -ps, I was writing this from the dad's perspective. I have a daughter who's twelve going on eighteen. No good.

[cjdbass]

It seems to me that kompreneble should mean "understandably," which has only a vaguely similar connotation to "of course."

[JohnMoser1]

I identified Kompreneble as an adjective modifying ŝlosos, but couldn't figure out what this meant in English. I got that the action of locking the room is understandable; the answer seems to suggest the action is obvious (of COURSE, duh, are you stupid or just stupid?).

[Matt-T-T]

How do we know it's not "the parent"

[dadatic]

Wouldn't "the parent" be "la gepatro"?

[kodanto]

The gender neutral form of parent is somewhat controversial. Since ge- denotes both genders instead of any gender, it's use for a singular noun is ambiguous. I've seen gepatrano (member of the parents) used as an alternative.

[dadatic]

I see. I was not aware of such controversy. In any case, "la patro" unambiguously means "the father", doesn't it?

[kodanto]

Correct. Patro father, patrino mother.