' Ti amo' or 'ti adoro' are more emphatically ' I love/adore you', while if you're letting someone down gently, you might say 'ti voglio bene' (I like you a lot), which is generally reserved for platonic love.
Two of the most common pet names in Italy are 'amore' (love) and 'tesoro' (treasure), but there are plenty of more evocative alternatives, from 'patatina' (little potato) to 'cucciolotto' (little puppy).
And just as in English, there's a risk that the romantic undertone might not be picked up on, so if you want to be clearer, you can say 'mi sono presa una cotta per qualcuno' (I have a crush on someone) or, stronger still, 'mi sono innamorarto/a in qualcuno' (I have fallen in love with someone).
There are a few different terms for flirting: the reflexive verb 'provarci' (roughly 'to try it on with'), the phrasal verb 'fare il filo a' or 'corteggiare' (literally 'to court') are more formal alternatives, or you can use the Anglicism 'flirtare', or 'civettare', though the latter is generally restricted to women.The noun 'una civetta', which means 'owl', is used to talk about flirty women (in English you might say 'vixen'), while for men you could say 'un donnaiolo' for a heterosexual man (it translates more or less as 'womanizer') or 'un cascamorto', which comes from the term 'cascare morto' (to fall down dead), suggesting dramatic swooning.You can also use the verbal phrase 'fare il cascamorto' to refer to a man who is flirting, usually in an over the top way, with someone.If you're talking directly to the object of your affections, make sure not to get confused by the verb 'piacere', which is often tough for non-native speakers.' Mi piaci' is ' I like you', while 'ti piaccio' means 'you like me'.Getting into a relationship with someone from another culture can be complex, as each culture places its own values on which qualities make someone a desirable partner.