amoureuse (feminine adjective) is 'in love' in French.
It's English transposed into French - I'm in love (we don't say this in French) - je suis amoureux/amoureuse de quelqu'un would be better.
je tombe amoureuse de toi means I'm falling in love with you (this is a girl speaking)
In French, you would say "Je suis amoureux de Kyle" if you are male, or "Je suis amoureuse de Kyle" if you are female. The phrase captures the sentiment of being in love with someone named Kyle.
Je suis tombé amoureux / tombée amoureuse de vous means 'I fell in love with you' in French. "tomber en amour" is a word-by-word translation from in English, but isn't correct French.
In love with life. It can only refer to a woman - if it was a male, it would be amoureux pour la vie.
The phrase "amorous liaison" in French can be translated as "liaison amoureuse". It refers to a romantic or sexual relationship between two people.
To fall in love is "tomber amoureux / amoureuse" in French.
Amoureux (masc.) and amoureuse (fem.) are the French adjectives derived from "amour".
the French translation of "I'm in love" is "je suis amoureux / amoureuse"
être amoureux (masc.) être amoureuse (femin.)
"Chèrie, est-tu amoureux/amoureuse?"
Je suis amoureuse de ce garçon.
I'm in love is spelled "je suis amoureux / je suis amoureuse" in French
je tombe amoureux, je tombe amoureuse
un amoureux des sacs / une amoureuse des sacs.
"je suis amoureux" for a man "je suis amoureuse" for a woman
In French, you can say "une liaison amoureuse" to refer to a love affair.