Kono Koi ni Kizuite THE ANIMATION

Tsujinaka-chan, a kouhai girl, invites her senpai who has been dumped by his girlfriend out for a drink to comfort him. Seeing him in a state of intense depression, the love she had been suppressing because he had a girlfriend overflows.... "Can I be your girlfriend?" "If you don't have a girlfriend, then you can love me with all your heart, right?♪" She forcibly takes the bewildered senpai to a love hotel...!

(Source: PinkPineapple, translated)