Question

Had her love been sincere he would not given him her up(Rewrite the sentence using adverb form of sincere) I have written Her love sincerely would not have given him her up ​

Answer 1

ʜᴇʏᴀ ᴍᴀᴛᴇ ʜᴇʀᴇ ɪs ʏᴏᴜʀ ᴀɴsᴡᴇʀ 
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according to me your answer can be:-

●Had she loved him sincerely, he would not have given her up.

Answer 2

If she would have loved him sincerely, he would not have given her up.

Seems the last part of your question is wrong!!!

'Not given him her up' makes no sense.

May be it is 'Not given her up'

I have wrote my answer according to the correct question.

Please recheck the question.

Hope this will help and mark me as brainliest if my answer helped you.