(И) РАД БЫ В РАЙ, ДА ГРЕХИ НЕ ПУСКАЮТ (saying) s.o. ( usu. the speaker) would like to do sth. , but cannot for reasons beyond his control: — I would if I could (, but I can't so I won't (shan't)).
(authors usage) «Документы?» Паспорт свой Влад подавал уже безо всякой надежды. И действительно, слегка полистав серую книжицу, кадровик безо всякого выражения обронил: «Не пойдет... Рад бы в рай, да, сам понимаешь, начальство мне оформление твое не санкционирует...» (Максимов 2). ( context transl ) "Papers?" Vlad handed over his passport, but without hope. As he had expected, having flipped through the gray booklet the man gave it back with an expressionless face and said: "No good .Myself, I'd be happy to take you on, but you know how it is