It's hard to put that into words. It would be better to write it out.
It's hard to explain this verbally. It's easier to put it on paper.
この場合、次のように言うと自然で良いでしょう。
ーIt's hard to put that into words. It would be better to write it out.
「それを言葉に表すのは難しい。書いたほうが良い」
to put ... into words で「言葉に表す・言い表す」
ーIt's hard to explain this verbally. It's easier to put it on paper.
「これを言葉で説明するのは難しい。紙に書くほうが簡単だ」
to explain ... verbally で「言葉で説明する・口頭で説明する」
to put ... on paper で「紙に書く・書き留める」
ご参考まで！
It's difficult to explain orally. If I could use a pen and paper...
It's difficult to put into words. It might be better to write it down.
「It's difficult to explain orally. If I could use a pen and paper...」という英文に書いた通り、伝えられるはずです。
別の言い方を知りたいなら、「It's difficult to put into words. It might be better to write it down.」と言えます。
最初の「It's difficult to put into words」というフレーズは直接言うは難しい時よく使います。そして、「 It might be better to write it down.」は「書いた方良いかもしれません」を表します。
ご参考になれば幸いです。
It's hard to explain. If I had a pen and paper it might be easier.
It's complicated. If I had a pen and paper it's easier for me to explain.
ご質問ありがとうございます。
・It's hard to explain. If I had a pen and paper it might be easier.
＝「説明が難しいです。ペンと紙があればもっと簡単かもしれません。」
（例文）Sorry, it's hard to explain. If I had a pen and paper it might be easier. I want to draw it.
（訳）すみません、説明が難しいです。ペンと紙があればもっと簡単かもしれません。その絵を描いてみたいです。
・It's complicated. If I had a pen and paper it's easier for me to explain.
＝「説明が複雑です。ペンと紙があればもっと簡単に説明できます。」
お役に立てれば嬉しいです。
Coco
カナダ 
アメリカ合衆国 
日本 
