zyoutokai ni sankasita monono, satooya ni naru ka kimete inai.

譲渡会 literally means something like transfer/adoption event.

In everyday Japanese, especially with animals, it usually refers to an adoption event where rescued cats or dogs are introduced to possible adopters. So in this sentence, it most likely means a pet adoption event.

• 譲渡 = transfer, handing over, adoption
• 会 = meeting, event, gathering

So this is not just any “meeting”; it is a specific kind of event for adoption.

Because 参加する normally takes に to mark what you participate in.

So:

• 譲渡会に参加する = to participate in / attend an adoption event

This is just the standard pattern:

• イベントに参加する = participate in an event
• 大会に参加する = participate in a tournament
• 会議に参加する = participate in a meeting

For English speakers, this can feel a little odd because English often uses in or no preposition at all, but in Japanese 参加する strongly prefers に.

Here, ものの means although, even though, or but.

So the structure is:

• 譲渡会に参加したものの、...
• Although (I/they) attended the adoption event, ...

It shows a contrast between what happened first and what happened after that. There is often a nuance of:

• something happened,
• you might expect a certain result,
• but that result did not happen.

Here, attending the adoption event might make you expect that the person would decide to become an adopter, but they still have not decided.

They are similar, but ものの is a bit more formal and often feels more written or explanatory.

Compare:

• 参加したけど、決めていない。
  Casual, everyday but

• 参加したが、決めていない。
  More formal/written but

• 参加したものの、決めていない。
  Although/even though, with a slightly stronger sense of contrast or “despite that”

So ものの is not just a plain connector. It often suggests: despite that fact.

Because なる does not take を for the thing you become. It usually uses に.

So:

• 里親になる = become an adoptive parent / foster parent / adopter
• 先生になる = become a teacher
• 大人になる = become an adult
• 静かになる = become quiet

This is the normal grammar pattern:

• Noun + に + なる
• na-adjective + に + なる
• i-adjective + く + なる

So 里親になる is exactly what you would expect grammatically.

Literally, 里親 means foster parent or adoptive parent. But with animals, it is often used to mean the person who takes the animal in and becomes its new caretaker.

In natural English, depending on the context, this could be:

• adopter
• new owner
• foster owner/family

In a pet adoption context, 里親になる often means to adopt the animal or to become the animal’s new guardian/home.

So even though the literal pieces look like village + parent, you should treat 里親 as one word with this established meaning.

Here, か marks an embedded question: whether.

So:

• 里親になるか決めていない
• have not decided whether to become an adopter

This pattern is very common:

• 行くか決める = decide whether to go
• 買うか考える = think about whether to buy it
• 本当か分からない = don’t know whether it’s true

So the sentence is not asking a direct question. Instead, か turns 里親になる into the content of the decision:

• whether to become an adopter

This is a very important transitive/intransitive distinction.

• 決める = to decide something
• 決まる = to be decided

So:

• 里親になるか決めていない = has not decided whether to become an adopter
• まだ決まっていない = it has not been decided yet

In this sentence, the focus is on the person actively making the decision, so 決める is used.

A quick comparison:

• 私はまだ決めていない。
  I haven’t decided yet.

• 日程はまだ決まっていない。
  The schedule hasn’t been decided yet.

Because the sentence describes two different time frames:

• 参加した = attending the adoption event happened in the past
• 決めていない = the state of not having decided continues up to now

So the meaning is basically:

• (They) attended the adoption event, but as of now, they still haven’t decided whether to become an adopter.

This is very natural in Japanese. The first action is a completed past event, while the second part describes the present situation.

Here it means has not decided.

With many verbs, 〜ている / 〜ていない can describe a resulting state rather than an action in progress. With 決める, 決めている often means has decided, and 決めていない means has not decided.

So:

• まだ決めていない = haven’t decided yet

It does not usually mean the person is in the middle of the action of “deciding” and is somehow not doing it at this exact second.

The subject is omitted, which is very normal in Japanese.

So depending on the context, it could mean:

• I attended the adoption event, but haven’t decided whether to become an adopter.
• They attended the adoption event, but haven’t decided whether to become an adopter.

Japanese often leaves out subjects when they are already understood from the situation. This is one of the biggest differences from English.

A helpful breakdown is:

• 譲渡会に参加した = attended the adoption event
• ものの = although / even though
• 里親になるか = whether to become an adopter
• 決めていない = have not decided

So the full structure is:

[Past action] + ものの + [whether-clause] + 決めていない

Or more abstractly:

Although X happened, Y has still not been decided.

That makes the sentence easier to read as a whole.