saijeuga an majeulkka bwa gateun oseul du saijeuro jumunhaesseoyo.

I ordered the same clothes in two sizes because I was worried one size might not fit.

Breakdown of saijeuga an majeulkka bwa gateun oseul du saijeuro jumunhaesseoyo.

• ~을: object particle
• ~가: subject particle
• 안: not
• 주문하다: to order

Questions & Answers about saijeuga an majeulkka bwa gateun oseul du saijeuro jumunhaesseoyo.

What does 안 맞다 mean here? I know 맞다 can mean to be correct.

In this sentence, 맞다 means to fit or to be the right size, not to be correct.

So:

• 사이즈가 맞다 = the size fits / the size is right
• 사이즈가 안 맞다 = the size doesn’t fit / the size is wrong

This is a very common use with clothes, shoes, rings, and so on.

Examples:

• 이 옷이 안 맞아요. = These clothes don’t fit.
• 신발 사이즈가 잘 맞아요. = The shoe size fits well.

So in your sentence, 사이즈가 안 맞을까 봐 means the speaker is worried the size might not fit.

What does -을까 봐 mean in 안 맞을까 봐?

-을까 봐 / -ㄹ까 봐 expresses worry, concern, or precaution about something that might happen.

Here, 맞을까 봐 literally has the idea of:

• I’m worried it might fit / might not fit
• and with 안, it becomes
• I’m worried it might not fit

So:

• 사이즈가 안 맞을까 봐 = because I was worried the size might not fit
• or more naturally, in case the size didn’t fit

A useful way to understand this pattern is:

possible bad situation + precautionary action

In this sentence:

• possible problem: 사이즈가 안 맞다
• precautionary action: 같은 옷을 두 사이즈로 주문했어요

So the speaker ordered two sizes as a precaution.

Why is it 사이즈가 and not ?