I have 2 dds aged 6 and 2. Long story short, i was a single mum to dd1 for her first 3 years and dd2 was born when she was 4. I am with dd2s dad and dd1 does not see her dad at all which obviously is a big issue for her in itself. To add to that, dd2 was an all consuming, breast fed, exhausting baby so taking all this into consideration I was expecting some sibling rivalry.
Ive tried my hardest to treat them equally, make time for both of them alone etc but there seems to be a deep set resentment towards dd2 from dd1.
Dd2 is a typical 2 year old, a pest, into everything, wanting to do everything her sister does and gets frustrated when she can't.
Dd1 (although is rarely forced unless the situation calls for it) despises holding her sisters hand, reluctantly says goodnight and will never say I love you. She hates sitting near her or playing with her and shows no caring instinct towards her if she hurts herself, struggles with something or gets upset.
There was a glimmer of hope today when dd2 fell asleep on the sofa and dd1 got her comforter and blanket for her to cover her. I could have cried when she showed me and I praised and praised her for being so kind to her sister and 'doesn't it feel nice to do something kind for her' to which she agreed. Fast forward a few hours and she's refusing to say goodnight or even make eye contact with her.
Does anyone have any tips? Any advise?
I've said to her things along the lines of how important it is to show her how to be a good sister/ be kind etc. She's learning from you, lead by example etc. I also reinforced the importance of sisters and how she will be your best friend forever if you let her and she'll be there for you forever.
I hate to see my usually kind dd1 act so dismissively of her sister and dd2s little face crumble when her love isn't reciprocated. I'd hate for their relationship to be ruined before it's had a chance to get going 
Thanks