Same way like Italian and Romanian and Spanish
You can perhaps argue Norwegian, Swedish and Danish are different dialects of the same language, or say the same for Portuguese and Galician but most linguists, Nordic and Iberian people will be offended by such a notion.
If you speak Italian to a Spanish person, they might be able to understand quite a lot but they'll know that you are speaking Italian. This is not always the case with Hindi and Urdu.
I also doubt they understand any Romanian at all.
> A statistical analysis sorting Romanian words by etymological source carried out by Macrea (1961)[88] based on the DLRM[99] (49,649 words) showed the following makeup:[89]
> 43% recent Romance loans (mainly French: 38.42%, Latin: 2.39%, Italian: 1.72%) 20% inherited Latin 11.5% Slavic (Old Church Slavonic: 7.98%, Bulgarian: 1.78%, Bulgarian-Serbian: 1.51%) 8.31% Unknown/unclear origin 3.62% Turkish 2.40% Modern Greek 2.17% Hungarian 1.77% German (including Austrian High German)[97] 2.24% Onomatopoeic If the analysis is restricted to a core vocabulary of 2,500 frequent, semantically rich and productive words, then the Latin inheritance comes first, followed by Romance and classical Latin neologisms, whereas the Slavic borrowings come third.