有以下三种方式表达真遗憾：
1、what a pity it is!，真遗憾！
2、I am so sorry for it!，我很抱歉！
3、I feel regretful for hearing that!，我为听到这件事感到遗憾！
根据您的描述，您也可以说Oh，really?! How come?!。从语气上就可以表达“遗憾”。
拓展资料：
1、对此表示遗憾
express regret over the matter;
2、十分遗憾地指出
point out with great [deep] regret;
3、终身遗憾
a lifelong regret;
4、很遗憾， 我不能去。
I am very sorry I won’t be able to go.
参考资料：
predestined relationship ； fate
缘 reason; cause; sake,relationship,edge; fringe,climb
无缘无故地 for no reason at all
世上没有无缘无故的爱，也没有无缘无故的恨。 There is absolutely no such thing
as love or hatred without any reason or cause.
不识庐山真面目，只缘身在此山中。 I can’t tell the true shape of Lu Shan
because I myself am on the mountain.
花径不曾缘客扫。 The garden path has never been cleared for the visit of a
guest.
血缘 blood relationship
人缘 relations with people
姻缘 predestined marriage
前世因缘 predestination
天赐良缘 a godsent marriage; a good marriage arranged in Heaven
天缘巧合 a luck coincidence
投缘的街坊们 congenial neighbors
化缘 beg for alms
有人缘 enjoy great popularity
喜结良缘 tie the nuptial knot
缔结姻缘 form marital tie
聊得投缘 talk congenially
有缘结识某人 be lucky to get acquainted with sb.
无缘结识某人 have no opportunity to get acquainted with sb.
与某人有一面之缘 happen to have met sb. once
婚姻是缘分。 A couple’s conjugal fate is prearranged.
他们的结合是美满的姻缘。 Their wedlock is a happy marriage.
有缘终相逢。 Fate brings together people who are far apart.
无缘不相逢。 There is no meeting without predestination.
我与烟酒无缘。 Smoking and drinking don’t appeal to me.
好事似乎与他无缘。 Good luck seemed to be wholly denied to him.
千里姻缘一线牵。 Two beings destined to marry each other, though thousands
of miles apart, are tied together with an invisible red thread by an old
man under the moonlight.
他们俩有情无缘。 The are attracted to each other but are not fated to be
conjugally tied.
机缘凑巧，我找到一份工作。 As luck would have it, I found a job.
，无缘对面不相逢。 As decreed by providence you have met him;
otherwise you might have failed although you traveled a long way.
我发现班里有几个同学和我挺投缘。 I found quite a few classmates congenial
to me.
我在班里有人缘。 I am popular with my classmates.
真遗憾,我们一直无缘相见。 It is a pity that we have no opportunity to meet
each other.