What does “水着勿体ないんでよかったら今度のお休み” mean here?

Question

水着勿体ないんでよかったら今度のお休み

Context: this girl sent this guy a picture of her in her swimsuit while she lay in bed because she just bought it and thought it was cute and just found out that her vacation trip to the beach was canceled because of a typhoon. The guy she sent the pic to was going to have to work while she was on vacation and was sad he couldn’t go with them. I imagine she was going to send him pics from the beach.

What’s she saying here? The translation provided says “ The swimsuit will go to waste so, this weekend” but I feel like this translation is incorrect/missing something because お休み doesn’t mean weekend.

Answer 1

I would translate the sentence as follows:

「水着勿体ない①んでよかったら②今度のお休み③…」

"Since [having bought] the swimsuit is such a waste/spoil① [because the reason I bought it was to use it at the beach but the plan has been cancelled], what about/if you want②, this holiday③... (let's go to the swimming pool④)"

① 勿体【もったい】ない is a Japanese word meaning "wasteful". For example, buying a cake to just eat some of it and leave most of it on the plate without eating it is 勿体ない.

② よかったら is used to introduce suggestion or a proposal. For example 「よかったら、映画【えいが】をみませんか。」（If you want, let's see a movie).

③ お休【やす】み stands for "holiday" or "day off".

④ As the user By137 pointed out in this comment, the sentence is not complete as it lacks a verb. Therefore I suggested a possible continuation of the sentence from the proposal introduced by よかったら② and the contextual information you provided. The full sentence in Japanese would be:

「水着勿体ないんでよかったら今度のお休みプールへ行きませんか。」