in english we use - me, you, him, her, it, us, you-all, them. for the accusative.
in rom, the nominative isn't required bc it is understood by the conjugation of the verb.
iubesc = I love. (I (eu) is in the nominative case )
iubesţi = you love. (you (tu) is in the nominative case)
The accusative asks the question next: who do you love? the answer is "you", of which you use the accusative pronoun. ("te" in this case). "te iubesc"
You'll see "mă, te,îl, o, ne, vă, îi, le" used for the accusative.
mă omori - you're killing me
te vreau - i want you

îl asculţi - (you) wait for him
Or with more stress (but i don't believe it's used often) is :
"te iubesc pe tine" - Is like saying "I love you (and not anyone else).
"te" is the unstressed version of the nominative pronoun "you". There is a stressed version which is "tine". The stressed always requires a preposition before it. (pe tine, cu tine, de tine, la tine, etc.)
mi-e dor de tine - I miss you
mi-a fost dor de tine - I've missed you.
locuieşti cu mine - You live with me.
...etc.