Doesn’t want to repay riba but also doesn’t want to give a bad impression
Question

                as-salaamu alaikum wa rahmatullahi wa
      barakatuhuplease inform we whether or not i must pay interest on loans i took out
      before coming to islam, or in my days of ignorance. i intend to pay off all of the
      principal ,of course, but i hate that i enter a state of war with Allah and His Messenger
      (SAW) because of fulfilling a haram contract that i entered while not knowing better. i
      would also hate to give muslims a bad name by not paying my debt conscientiously. can i
      pay of the principal and give a gift stipulating that i reject riba and that i am only
      giving this extra sum for another reason?may Allah subhanu wa ta'Ala reward you with the good.
Praise be to Allah.If you are able to, then do not pay the interest, 
  so that you will not be counted among those referred to in the hadeeth: The 
  Messenger of Allaah  (peace and blessings of Allaah 
  be upon him) cursed the one who consumes riba, the one who pays it, the one 
  who writes it down and those who witness it, and said that all are equally sinful. 
  (Reported by Muslim, 2995). All of them are cursed for 
  their participation in this sin.
In order for a Muslim to avoid giving a bad impression to the 
  people from whom he took out the loan and who may be unaware of the fact that 
  it is forbidden, if he does not want to pay the interest, he could explain to 
  them the shari reason for this. If you have no choice and are forced to 
  pay the interest, unwillingly, then your repentance should be sufficient, in 
  sha Allaah.
For more information, please see Questions # 824 
  and 2492.
May Allaah bless our Prophet Muhammad.