This was written by George Merrill and Shannon Rubicam.  According to them …

George: “They asked us to write for Janet Jackson’s next record, so Shannon and I went to work and came up with our song How Will I Know, which was sent to Janet Jackson’s people. They passed on it because it wasn’t right for her at the time – she was in the midst of doing her Control album.

Shannon: “It wasn’t right for that, but then our publishing company played it for Gerry Griffith when he was in Los Angeles gathering material for the unknown Whitney Houston. He loved it, sent it to Clive (Davis), and Clive said, ‘We must have it.’ And we said, ‘Whitney who? Clive who?’

George: “Shannon and I had our first record deal, so we were caught up in Boy Meets Girl land, and the idea of writing for other people, this is pre-Whitney Houston and pre- our understanding of songwriting for other people, so it was really a big deal when they wanted to hold onto this for Whitney Houston. Then we started checking into it and thought, well, this could be kind of a neat deal. Our good friends, brother team Alan and Preston Glass, called us where they were working with Narada Michael Walden. They were recording Whitney Houston on ‘How Will I Know’ and they said, ‘Guys, you’ve got to hear this.’ They played it over the phone, and I swear, her voice, hearing the first take of ‘How Will I Know’ on the phone we knew we were on to something special, too.”

Interestingly, the backing vocals are by Whitney’s mother, Cissy Houston.

George and Shannon also wrote Houston’s hit I Wanna Dance With Somebody (Who Loves Me).

How Will I Know
Whitney Houston

There’s a boy I know, he’s the one I dream of
Looks into my eyes, takes me to the clouds above, mmm-hmm
Oh, I lose control, can’t seem to get enough, uh-huh
When I wake from dreaming, tell me is it really love

Ooh, how will I know (don’t trust your feelings)
How will I know
How will I know (love can be deceiving)
How will I know

How will I know if he really loves me?
I say a prayer with every heartbeat
I fall in love whenever we meet
I’m asking you what you know about these things
How will I know if he’s thinking of me
I try to phone but I’m too shy (can’t speak)
Falling in love is so bittersweet
This love is strong, why do I feel weak?

Oh, wake me, I’m shaking, wish I had you near me now, uh-huh
Said there’s no mistaking, what I feel is really love

Ooh, tell me how will I know (don’t trust your feelings)
How will I know
How will I know (love can be deceiving)
How will I know

How will I know if he really loves me?
I say a prayer with every heartbeat
I fall in love whenever we meet
I’m asking you what you know about these things
How will I know if he’s thinking of me
I try to phone but I’m too shy (can’t speak)
Falling in love is so bittersweet
This love is strong, why do I feel weak?

If he loves me
If he loves me not
If he loves me
Ooh, if he loves me not
Hey, if he loves me
If he loves me not

Oh, how will I know, how will I know
How will I know
Hey, how will I know

Ooh, how will I know if he really loves me?
I say a prayer with every heartbeat
I fall in love whenever we meet
I’m asking you ’cause you know about these things
How will I know if he’s thinking of me
I try to phone but I’m too shy (can’t speak)
Falling in love is so bittersweet
This love is strong, why do I feel weak?

How will I know (how will I know)
How will I know
How will I know (I say a prayer)
How will I know
Ooh, how will I know (I fall in love)
How will I love, hey, how will I know?

Source: LyricFind
Songwriters: George Robert Merrill / Narada Michael Walden / Shannon Rubicam
How Will I Know lyrics © Universal Music Publishing Group