Can I marry my fiance without letting out parents know, so we can hangout together, and do the nikah again in 2 years time?

Rasulullah (Sallallaahu Alayhi Wasallam) advised, 'Announce the Nikah.' (Mishkaat)

The wisdom behind the announcement is to avoid any misconception of an illegal and illicit relationship between the boy and girl. Although the first and secret marriage for the purpose of legalizing intimacy will be valid and the relationship between the boy and girl will not be prohibited, but we are also advised to abstain from doubt and disgrace. If the Nikah is not announced, people witnessing the relationship will regard the relationship as Haraam and illegal. That is very disgraceful.

Furthermore, what if the girl conceives and gives birth before the official 'second' marriage. That child will be regarded as an illegitimate child in public. The
negative factors surrounding that as well as the child for the rest of his life are well known. Therefore, we advise that if there is a dire need to fulfil one's desires, the Nikah be expediated to avoid the abovementioned negative factors of a secret marriage.

and Allah Ta'ala Knows Best

Mufti Ebrahim Desai
FATWA DEPT.