That is more likely that they will give testimony according to its (5:108)

﴿ذَٰلِكَ أَدْنَىٰ أَن يَأْتُوا بِالشَّهَادَةِ عَلَىٰ وَجْهِهَا أَوْ يَخَافُوا أَن تُرَدَّ أَيْمَانٌ بَعْدَ أَيْمَانِهِمْ ۗ وَاتَّقُوا اللَّهَ وَاسْمَعُوا ۗ وَاللَّهُ لَا يَهْدِي الْقَوْمَ الْفَاسِقِينَ﴾
[ المائدة: 108]

5:108 That is more likely that they will give testimony according to its [true] objective, or [at least] they would fear that [other] oaths might be taken after their oaths. And fear Allah and listen; and Allah does not guide the defiantly disobedient people.

These various oaths to be taken by the witnesses after the prayer ( when you doubt their testimony ) and the rejection of their testimony increases the likelihood that they will testify in the way required by the sacred law, without them distorting the facts deceitfully.
Witnesses are more likely to give true testimony for fear that they will be disgraced if the heirs give conflicting testimony.
Be mindful of Allah by not lying or being deceitful in your testimony and oath.
Listen to what you are instructed to do and obey.
Allah does not guide those who go against Him.

That should make it closer (to the fact) that their testimony would be in its true nature and shape (and thus accepted), or else they would fear that (other) oaths would be admitted after their oaths. And fear Allah and listen (with obedience to Him). And Allah guides not the people who are Al-Fasiqun (the rebellious and disobedient).

phonetic Transliteration

Thalika adna an yatoo bialshshahadati AAala wajhiha aw yakhafoo an turadda aymanun baAAda aymanihim waittaqoo Allaha waismaAAoo waAllahu la yahdee alqawma alfasiqeena

Abdullah Yusuf Ali - Translation

That is most suitable: that they may give the evidence in its true nature and shape, or else they would fear that other oaths would be taken after their oaths. But fear Allah, and listen (to His counsel): for Allah guideth not a rebellious people:

Safi-ur-Rahman al-Mubarakpuri

That should make it closer (to the fact) that their testimony would be in its true nature and shape, or else they would fear that (other) oaths would be admitted after their oaths. And have Taqwa of Allah and listen (with obedience to Him). And Allah guides not the rebellious people.

Page 125 English transliteration