amo

Amo, amare, amavi, amatum, first conjugation, and the paradigm verb of that conjugation for the excellent reason that it never does anything surprising. It takes a plain accusative of whoever or whatever is loved.

The useful distinction is with diligo. Amare is the warm word, covering affection and desire alike; diligere is cooler and more deliberate, love as a considered choice, and the Vulgate switches between them in ways that theologians have argued over for centuries. The present participle amans works as a noun meaning "lover", and amabo te, literally "I shall love you", is Latin for "please". English took amateur, amiable, amorous and enamoured, and the imperative ama went straight into Spanish and Italian without stopping.