I don't think she'd have said it if she didn't.

I agree with you, i see in her eyes when she said i love you

Joss Whedon's instructions to the actors for that scene pretty much say she did - he told Sarah to mean it when she said she loved him, and James to mean it when he said no you don't.

Spike wasn't the one who she gave the cookie dough speech to because that was Angel. I believe in my heart that Angel was the one she truly loved.

^The cookie dough speech was more "I don't know who I want to spend my life with because I'm not done maturing yet" rather than "it's you I want to be with once I'm done maturing". I agree that Angel was one of the options she had in mind at the time, or otherwise she'd have corrected him when he said that he isn't getting any older. Basically, at that point she's meant to be equally in love with both souled vampires. Fans' interpretations tend to biased depending on their favourite pairing or character though.