Sheikh Fawzān – may Allāh preserve him – said:-

If a Muslim is certain that he performed wuḍū (ritual ablution) and suspects he has broken it, he is still in a state of wuḍū (ritual ablution), because that is the default unless something happens to change it: It was narrated by Abū Hurayrah (may Allāh be pleased with him) that Allāh’s Messenger (May Allāh praise him and Peace be upon him) said, “When one of you finds something in his abdomen and he is not sure whether something came out of him or not, nothing has come out of him unless he heard or smelt something” [Ṣaḥīḥ Muslim: 362].