Lying to girls no matter how trivial or small is just generally a bad idea. I've always said that I think girls have some sixth sense, and if you lie to them they'll eventually find out anyways. Maybe in a few days, couple of weeks, or even months. The point is, they will find out in the end and you will be in for some drama and bitchiness. And you'll probably deserve it, even if it feels out of proportion with the lie.
Lying isn't bring congruent and it makes you less attractive, the opposite of what you're going for. Even if it's something that could potentially make her upset, it's much better getting it over and done with now by telling her the truth than it is to leave it and deal with a much bigger situation later.
One example I could give is when I was starting a long-distance relationship with Anna, a Finnish girl I met in Rome while traveling. Personally I'm not really for monogamy anyways, but with the addition of spending months apart I knew I'd sleep with other girls. So I just said, "I want to be with you but I can't promise I won't sleep with other girls, I know I would eventually just cheat on you." She was understandably a little taken aback at first, but soon as I explained myself and told my honest thoughts about it all, she came around to the idea of having an open relationship. This saved me a lot of hassle in the future because she most definitely would have found out, there would have been a massive fight and potentially the relationship could've ended. But this way I could sleep around without without having to hide anything or feel guilty about it at all.
Don't pretend to like something she likes just because she likes it. Don't say you can give her the world when all you want is a booty call or fwb. Don't tell her something just because you think it's what she wants to hear.
Telling her the truth just straight up is quite bold, you stand miles apart from other guys. Just as lying is an unattractive trait, telling the truth straight up is and attractive trait. To be able to nicely just say what's up, so she knows where she stands will make you more attractive. Think of it as an investment: you're being congruent with what you want even in the face of a little disagreement for the sake of much better outcomes later on.
Of course I'm still guilty of lying myself, it's a hard thing to never lie. However pretty much every time I'm reminded later as to why I have this rule by some deserved drama and anger. So think about your future self and try not to lie to girls. You might save yourself a little drama or hassle today, but it'll come back 10x worse, for sure. And in reverse, by being honest you're actually being a strong, stable, congruent guy. From a girl's point of view, that's pretty attractive.
*Note: attraction and frustration often come hand in hand. If you tell her something and she finds it quite frustrating and annoying (ie, you don't want anything more than fb), don't equate this with her becoming less attracted to you. It's nearly always the opposite.