Advice on whether or not she likes me or not - please help I'm confused?

Hello, right basically my mates ex-girlfriend whom he has a kid with and still lives with I'm unsure about, when we text eachother we always have put "xxxxxx" on the end of the texts, she always says she needs someone to love and when I was around yesterday when we was watching the TV it was on a break and my mate went to the toilet and she looked at me and I looked back and like we caught eachothers attention and looked at eachother and smiled and then all during the night I seen her keep looking at me and smiling and she even says she is single and just wants someone, how do I know if she likes me or not? Is putting "xxxxxx" on the end of a text a signal?