Originally Posted by Vinayakan

Eliza and Jonny in Devanagari, but not Sanskrit. Rather Hindi or Marathi.
Elīzā - एलीज़ा Jônī - जॉनी

Being in love is not a whole sentence. Who is in love, what kind of love?
I (male) am in love with you = त्वय्यनुरक्तोऽस्मि। tvayyanurakto'smi.
I (fem.) am in love with you = त्वय्यनुरक्तास्मि। tvayyanuraktāsmi.
Above is in Sanskrit.