To fall for
To become very attracted to
E.g. I think I’ve fallen for the new guy who has just started working in our office.
To fit in
To feel happy in a group of people because you are similar to them
E.g. He fitted in the new team at once.
To get along
To like each other and be friendly
E.g. We get along very well, but occasional rows are imminent.
To ask out
To invite someone to go to a place like a cinema or a restaurant, usually to start a romantic relationship
E.g. He seems to be quite into me, but he hasn’t asked me out yet.
To go out with sb
To have a romantic relationship with sb
E.g. I’ve been going out with my boyfriend for ten months now and we are planning to get married next year.
To fall out
To have an argument or a row
E.g. Last week my girlfriend and I fell out over something really stupid.
A way of talking which suggests you are sexually attracted to someone and want them to be attracted to you (from the verb chat up)
E.g. He heard a make friend of mine tell me my hair looked nice and he thought it was a chat-up line, so now he doesn’t want to speak to me.
Hit it off with sb
Immediately like sb and become friendly with them
E.g. Barry and David hit it off immediately when they first met.
To pair off with sb
To start a romantic relationship with sb
E.g. Nigel paired off with Alice at the party last night, and I am the one left feeling jealous.
To turn sb on
To make sb interested, often sexually
E.g. This girl really turns me on! She is so gorgeous.