Mewn canol y haf, tŵr swyddfa mawr yng nghanol Caerdydd yn sgleinio yn yr haul.

In the middle of the summer, a large office tower in the center of Caerdydd was shining in the sun.

Roedd y gwydr modern yn adlewyrchu golau disglair y ddinas brysur.

The modern glass reflected the bright light of the busy city.

Y tu mewn, roedd yna symudiad cyson, gyda phobl yn gweithio'n galed.

Inside, there was constant movement, with people working hard.

Roedd cyfeillgarwch yn amlwg wrth i gydweithwyr chwerthin dros baned o goffi neu rannu straeon.

Friendship was evident as colleagues laughed over a cup of coffee or shared stories.

Roedd Geraint yn eistedd wrth ei ddesg newydd.

Geraint was sitting at his new desk.

Roedd yn teimlo cyfnod o lawenydd a balchder wedi iddo glywed ei fod wedi cael dyrchafiad.

He felt a moment of joy and pride after hearing he had been promoted.

Roedd hyn yn golygu llawer iddo.

This meant a lot to him.

Wedi misoedd o waith caled, roedd ei freuddwydion o fynediad i’r uwch don yn dod yn wir.

After months of hard work, his dreams of access to the senior tier were coming true.

Ond roedd ton o wybodaeth newydd yn troi'n lwc iddo - roedd Rhian, ei gydweithiwr a ffrind, wedi colli ei swydd i wneud lle iddo.

But a wave of new information turned lucky for him - Rhian, his colleague and friend, had lost her job to make room for him.

Geraint wnaeth glywed hyn gan ei gydweithiwr, Dafydd.

Geraint heard this from his coworker, Dafydd.

Roedd e'n cefnogi Geraint, ond roedd yn deall ei ofid.

He supported Geraint, but he understood his distress.

"Mae'n anghywir, Geraint," meddai Dafydd.

"It's wrong, Geraint," said Dafydd.

"Roedd Rhian yn werthfawr iawn i'r cwmni.

"Rhian was very valuable to the company."

"Roedd Geraint yn meddwl am y tro diwethaf y siaradodd â Rhian.

Geraint thought about the last time he spoke to Rhian.

Roedd hi bob amser yn berson gonest, yn gweithio'n galed, ac roedd ganddi wnaed cyfraniadau hanfodol.

She was always an honest person, worked hard, and made essential contributions.

Roedd meddwl bod ei lwyddiant ef wedi gostio ei lle hi yn gwneud i'w galon cyrcynu yn euog.

The thought that his success had cost her place made his heart shrink with guilt.

Er mwyn datrys hyn, penderfynodd Geraint na allai ohirio mwyach.

To resolve this, Geraint decided he could not delay any longer.

Aeth i mewn i ystafell gyfarfod, a chafodd alwad brys gyda'r tîm rheoli.

He went into a meeting room and made an urgent call with the management team.

Paratodd dystiolaeth o waith gwerthfawr Rhian.

He prepared evidence of Rhian's valuable work.

Ysgrifennodd restr o'i chyflawniadau a'r ffordd roedd hi wedi tynnu'r cwmni i ben.

He wrote a list of her achievements and how she had elevated the company.

Pan oedd y cyfarfod yn dechrau, roedd nerfusrwydd yn bragu y tu mewn iddo.

When the meeting began, nervousness was brewing inside him.

Ond pan siaradodd, roedd ei eiriau'n glir ac yn onest.

But when he spoke, his words were clear and honest.

"Mae Rhian wedi gwneud cyfraniadau sydd wedi bod yn hanfodol i'r cwmni," meddai.

"Rhian has made contributions that have been essential to the company," he said.

"Mae'n annheg iddi golli ei swydd.

"It's unfair for her to lose her job.

Rwy'n credu y dylai gael cyfle arall.

I believe she should be given another opportunity."

"Roedd tensiwn ar wynebau'r rheolwyr.

There was tension on the managers' faces.

Ond, yn araf ond yn sicr, roeddent yn cydnabod pwyntiau Geraint.

But, slowly but surely, they acknowledged Geraint's points.

Cytunwyd i gynnig rôl arall i Rhian mewn adran wahanol.

It was agreed to offer Rhian another role in a different department.

Roedd Geraint yn cadw ei ddyrchafiad, ond teimlodd bod yna gyfiawnder wedi bod.

Geraint kept his promotion, but he felt that justice had been served.

Yn y diwedd, dysgodd Geraint werth tryloywder ac uniondeb.

In the end, Geraint learned the value of transparency and integrity.

Fe sylweddolodd bod llwyddiant yn ddi-werth os yw'n seiliedig ar ddymchwel eraill.

He realized that success is worthless if it is based on undermining others.

Roedd yn barod i wynebu'r byd corfforaethol gyda mwy o hyder, ond gyda chanolbwynt newydd - nid yn unig i lwyddo, ond i wneud hynny gyda mynegiant gonest o'i werthoedd a’i ffrindiau.

He was ready to face the corporate world with more confidence, but with a new focus - not only to succeed but to do so with an honest expression of his values and his friends.