"Esperar" is already in the Spanish infinitive form. It means "to wait" or "to hope". Infinitives of verbs are identified by the last two letters, either "er", "ir", or "ar". Overall, the "ar" variety is most common, but many high-useage verbs are in the ohter two categories.
esperar
esperar
Vamos a esperar
We say "No puedo esperar"
No puedo esperar
en no esperar a verte mañana
No puedo esperar hablar Español - I can't wait to speak Spanish No puedo esperar hasta que pueda hablar español - I can't wait until I can speak Spanish
No puedo esperar a amarte
No puedo esperar verla.
No (spanish accent) puedo esperar Asta chilpayate this is Spanish accent :-)
You could say "Es duro esperar". Probably it would be better to say "Es difìcil esperar", which is "it is difficult to wait".
Wait is "esperar" pernounced; ehs-pehr-ahr