I guess you might have been busy. I'm here when you want to chat.
I know you're busy. You can get back to me whenever you're free.
ちょっとカジュアルな印象ですが、「〜なのかな」と言いたい際は I guess を用いると良いのではと思います。他にも、I know でも感じは悪くならないと思います。
「時間がある時」なので、when/whenever you're free や when you want to chat/talk がシンプルで良いでしょう。When you want to --- は、相手にスペースを与えている感があって、決して押し付ける印象は残しませんよ。
「忙しい」で英文例には busy と載せましたが、もし相手がいろいろな事情で忙しいことを知っていたとしたら、I know/I guess you have a lot going on も使えますよ。
"Hey, I know you have a lot going on. I'm here whenever you want to talk."
こんな感じで表現できるかと思います。
参考までに（＾＾）
1. Don't worry about replying quickly - it's not urgent!
2. If you're busy, just reply anytime you like.
Probably it is better to send one of these messages with the original message. The person receiving your message will understand that you know he has read the message and has not replied. When you write again, they will believe that you really are waiting for a reply quickly!
No worries, if you're busy just reply when you can
Feel free' is a phrase we use to let a person know they are free to make a choice or decision without being under pressure from anyone else.
For example, you could say to a guest in your house: "Feel free to help yourself to anything to eat".
Feel free' は誰からのプレッシャーを感じずに自由に選択や決定をしてほしいという意図を相手に示す表現です。
例えば、あなたの家を訪ねてきたお客さんには次のように言えるでしょう。
"Feel free to help yourself to anything to eat".
（なんでも食べたいものを自由に食べてくださいね。）
Sometimes it is nice to let people know that they do not have to reply/answer straight away. We are all very busy at work
There is "no hurry", reply when you have a moment.
I know you are busy, there is "no" need to "rush", reply when you can.
I do not need a "swift" response, reply at your earliest convenience.
"皆さんそれぞれ仕事があって忙しいですよね、だからすぐに返信したり返事をする必要はないですよ、と伝えると良い場合もありますね。
例文です。
・There is ""no hurry"", reply when you have a moment.
""there is no hurry""＝「急ぎませんので」という意味の成句。
・I know you are busy, there is ""no"" need to ""rush"", reply when you can.
""no need to rush""＝「急ぐ必要はないよ」
・I do not need a ""swift"" response, reply at your earliest convenience.
""swift""＝速い、迅速な。
""responce""＝応答
""convienience""＝好都合（なこと）、便利
""at your earliest convienience""＝「ご都合つき次第に」というビジネスでよく使われる成句。
Heya I know you're busy right now, hope to hear from you later :)
Heya let me know when you're free to chat.
Hi hope to talk later when you're not busy!
Heya I know you're busy right now, hope to hear from you later :)
Heya let me know when you're free to chat.
Hi hope to talk later when you're not busy!
'when you're not busy' - same meaning as free.
'hope to hear from you soon'- meaning- I hope to get a reply from you soon!
** You can also say:** Casual phrases:
* I know you're busy so message back whenever!
*Its not super urgent so just reply when you're free!
*Message back whenever!
All of these phrases are casual, if you'd like more formal ones, use the first 3 at the top of this answer :)
Hope this helps! ^^
Heya I know you're busy right now, hope to hear from you later :)
やぁ、今忙しいのはわかってるんだけど、また返事もらえるのを待ってます。
Heya let me know when you're free to chat.
話せるときまた教えてね。
Hi hope to talk later when you're not busy!
やぁ、忙しくないときにまた話せたらいいな。
'when you're not busy' - 暇なときにという意味です。
'hope to hear from you soon'- 返事を待っていますという意味です。
また以下のようにカジュアルな表現を使うこともできます。
* I know you're busy so message back whenever!
忙しいのわかってるから、いつでも返信してね！
*It's not super urgent so just reply when you're free!
急ぎじゃないから、時間のある時に返事してね！
*Message back whenever!
いつでも返事ちょうだいね！
これらは全てカジュアルな表現なので、かしこまった表現の方がよければ、最初の3つを使うことをお勧めします。
I know you're busy right now so just give me a bell when you're free
"I know you're busy right now" is a polite way to excuse someone from not replying immediately to your message because they may have been busy with other things.
Give me a bell when you're free - To give some one a bell means to call someone. The saying originates from when we had telephones that rang with a bell.
So this is a good phrase to use when you want some to call you as soon as they have some free time.
"I know you're busy right now" （あなたが忙しいのは分かっています）は、他のことで忙しかったかもしれないので、あなたのメッセージにすぐに返信しなかったことを咎めない丁寧な表現です。
例文
Give me a bell when you're free
暇な時に電話して
To give some one a bellは人に電話することです。
この表現は、電話がベルでなっていた時代に由来しています。
だから、時間が出来次第すぐに電話をして欲しい時に使うと良い表現です。
Are you busy? Please call me back when you have the time.
I know you are busy so please give me a ring when you have time.
Both of these examples are correct.You will come across as being polite and understanding when you use both. We use "ring" when we talk about calling someone. "ring" is the sound that the old landline telephones use to make when someone calls you.
Reply when you have some free time if you are busy at the minute.
Take your time to reply, there is no rush.
Hey, I know that you might be a little busy right now, so, message me back when you have some free time, there is no rush to reply, take your time.
I hope that helps.
Have a great day.
Will
Here are two example sentences that we can use for this idea while also showing you the ways in which we can move around and restructure English sentences. Notice that, "reply to me later," can either come at the beginning or the end of the phrase.
You are surely busy, reply when you have the time.
You must be busy, respond when you get a chance.
You can use any of the above two sentences to tell someone if they are busy that is okay and that they can reply when they get a chance.
Example;
- You must be very busy, please respond when you get the chance.
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