In real life it doesn't necessarily follow that, because a fellow admires a girl's hair and eyes, and wants to be on friendly terms, he is in love with her.
For example, he emphatically was not in love with Mona Stevens.

He only wanted her to be decently civil and to stop holding a foolish grudge against him for not standing up and letting himself be shot full of holes because she commanded it.
In the afternoons, Mrs.Stevens would sit beside him and knit things and talk to him in a pleasantly garrulous fashion, and he would lie and listen to her--and to Mona, singing somewhere.

Mona sang very well, he thought; he wondered if she had ever had any training.

Also, he wished he dared ask her not to sing that song about "She's only a bird in a gilded cage." It brought back too vividly the nights when he and Bob stood guard under the quiet stars.
And then one day he hobbled out into the dining-room and ate dinner with the family.

Since he sat opposite Mona she was obliged to look at him occasionally, whether she would or no.